14 (fourteen) is the
natural number
In mathematics, the natural numbers are the numbers 0, 1, 2, 3, and so on, possibly excluding 0. Some start counting with 0, defining the natural numbers as the non-negative integers , while others start with 1, defining them as the positive in ...
following
13 and preceding
15.
Mathematics
Fourteen is the seventh
composite number
A composite number is a positive integer that can be formed by multiplying two smaller positive integers. Accordingly it is a positive integer that has at least one divisor other than 1 and itself. Every positive integer is composite, prime numb ...
.
Properties
14 is the third distinct
semiprime, being the third of the form
(where
is a higher prime). More specifically, it is the first member of the second cluster of two discrete
semiprimes (14,
15); the next such cluster is (
21,
22), members whose sum is the fourteenth prime number,
43.
14 has an
aliquot sum
In number theory, the aliquot sum of a positive integer is the sum of all proper divisors of , that is, all divisors of other than itself.
That is,
s(n)=\sum_ d \, .
It can be used to characterize the prime numbers, perfect numbers, sociabl ...
of
10, within an
aliquot sequence
In mathematics, an aliquot sequence is a sequence of positive integers in which each term is the sum of the proper divisors of the previous term. If the sequence reaches the number 1, it ends, since the sum of the proper divisors of 1 is 0.
Def ...
of two composite numbers (14,
10,
8,
7,
1, 0) in the prime 7-aliquot tree.
14 is the third
companion Pell number and the fourth
Catalan number
The Catalan numbers are a sequence of natural numbers that occur in various Enumeration, counting problems, often involving recursion, recursively defined objects. They are named after Eugène Charles Catalan, Eugène Catalan, though they were p ...
. It is the lowest even
for which the
Euler totient has no solution, making it the first even
nontotient
In number theory, a nontotient is a positive integer ''n'' which is not a totient number: it is not in the range of Euler's totient function φ, that is, the equation φ(''x'') = ''n'' has no solution ''x''. In other words, ''n'' is a nontotie ...
.
According to the
Shapiro inequality
In mathematics, the Shapiro inequality is an inequality proposed by Harold S. Shapiro in 1954.
Statement of the inequality
Suppose is a natural number
In mathematics, the natural numbers are the numbers 0, 1, 2, 3, and so on, possibly exc ...
, 14 is the least number
such that there exist
,
,
, where:
:
with
and
A
set
Set, The Set, SET or SETS may refer to:
Science, technology, and mathematics Mathematics
*Set (mathematics), a collection of elements
*Category of sets, the category whose objects and morphisms are sets and total functions, respectively
Electro ...
of
real number
In mathematics, a real number is a number that can be used to measure a continuous one- dimensional quantity such as a duration or temperature. Here, ''continuous'' means that pairs of values can have arbitrarily small differences. Every re ...
s to which it is applied
closure and
complement operations in any possible sequence generates 14 distinct sets. This holds even if the reals are replaced by a more general
topological space
In mathematics, a topological space is, roughly speaking, a Geometry, geometrical space in which Closeness (mathematics), closeness is defined but cannot necessarily be measured by a numeric Distance (mathematics), distance. More specifically, a to ...
; see
Kuratowski's closure-complement problem
In point-set topology, Kuratowski's closure-complement problem asks for the largest number of distinct sets obtainable by repeatedly applying the set operations of closure and complement to a given starting subset of a topological space. The an ...
.
There are fourteen
even numbers that cannot be expressed as the sum of two odd
composite number
A composite number is a positive integer that can be formed by multiplying two smaller positive integers. Accordingly it is a positive integer that has at least one divisor other than 1 and itself. Every positive integer is composite, prime numb ...
s:
:
where 14 is the seventh such number.
Polygons
14 is the number of
equilateral triangle
An equilateral triangle is a triangle in which all three sides have the same length, and all three angles are equal. Because of these properties, the equilateral triangle is a regular polygon, occasionally known as the regular triangle. It is the ...
s that are formed by the
sides and
diagonal
In geometry, a diagonal is a line segment joining two vertices of a polygon or polyhedron, when those vertices are not on the same edge. Informally, any sloping line is called diagonal. The word ''diagonal'' derives from the ancient Greek � ...
s of a
regular six-sided
hexagon
In geometry, a hexagon (from Greek , , meaning "six", and , , meaning "corner, angle") is a six-sided polygon. The total of the internal angles of any simple (non-self-intersecting) hexagon is 720°.
Regular hexagon
A regular hexagon is de ...
. In a
hexagonal lattice
The hexagonal lattice (sometimes called triangular lattice) is one of the five two-dimensional Bravais lattice types. The symmetry category of the lattice is wallpaper group p6m. The primitive translation vectors of the hexagonal lattice form an ...
, 14 is also the number of fixed two-dimensional
triangular-celled
polyiamond
A polyiamond (also polyamond or simply iamond, or sometimes triangular polyomino) is a polyform whose base form is an equilateral triangle. The word ''polyiamond'' is a back-formation from ''diamond'', because this word is often used to describ ...
s with four cells.
14 is the number of
elements in a
regular heptagon (where there are seven
vertices and edges), and the total number of
diagonal
In geometry, a diagonal is a line segment joining two vertices of a polygon or polyhedron, when those vertices are not on the same edge. Informally, any sloping line is called diagonal. The word ''diagonal'' derives from the ancient Greek � ...
s between all its vertices.
There are fourteen polygons that can fill a
plane-vertex tiling, where five polygons tile the plane
uniformly, and nine others only tile the plane alongside irregular polygons.

The
Klein quartic is a compact
Riemann surface
In mathematics, particularly in complex analysis, a Riemann surface is a connected one-dimensional complex manifold. These surfaces were first studied by and are named after Bernhard Riemann. Riemann surfaces can be thought of as deformed vers ...
of genus 3 that has the largest possible
automorphism group
In mathematics, the automorphism group of an object ''X'' is the group consisting of automorphisms of ''X'' under composition of morphisms. For example, if ''X'' is a finite-dimensional vector space, then the automorphism group of ''X'' is the g ...
order of its kind (of order
168) whose fundamental domain is a regular hyperbolic 14-sided
tetradecagon, with an area of
by the
Gauss-Bonnet theorem.
Solids
Several distinguished
polyhedra
In geometry, a polyhedron (: polyhedra or polyhedrons; ) is a three-dimensional figure with flat polygonal faces, straight edges and sharp corners or vertices. The term "polyhedron" may refer either to a solid figure or to its boundary su ...
in
three dimensions contain fourteen
faces or
vertices as
facets:
* The
cuboctahedron
A cuboctahedron is a polyhedron with 8 triangular faces and 6 square faces. A cuboctahedron has 12 identical vertex (geometry), vertices, with 2 triangles and 2 squares meeting at each, and 24 identical edge (geometry), edges, each separating a tr ...
, one of two
quasiregular polyhedra, has 14 faces and is the only
uniform polyhedron
In geometry, a uniform polyhedron has regular polygons as Face (geometry), faces and is vertex-transitive—there is an isometry mapping any vertex onto any other. It follows that all vertices are congruence (geometry), congruent. Uniform po ...
with
radial equilateral symmetry.
* The
rhombic dodecahedron
In geometry, the rhombic dodecahedron is a Polyhedron#Convex_polyhedra, convex polyhedron with 12 congruence (geometry), congruent rhombus, rhombic face (geometry), faces. It has 24 edge (geometry), edges, and 14 vertex (geometry), vertices of 2 ...
,
dual to the cuboctahedron, contains 14 vertices and is the only
Catalan solid
The Catalan solids are the dual polyhedron, dual polyhedra of Archimedean solids. The Archimedean solids are thirteen highly-symmetric polyhedra with regular faces and symmetric vertices. The faces of the Catalan solids correspond by duality to ...
that can
tessellate space.
* The
truncated octahedron
In geometry, the truncated octahedron is the Archimedean solid that arises from a regular octahedron by removing six pyramids, one at each of the octahedron's vertices. The truncated octahedron has 14 faces (8 regular hexagon, hexagons and 6 Squa ...
contains 14 faces, is the
permutohedron of order four, and the only
Archimedean solid
The Archimedean solids are a set of thirteen convex polyhedra whose faces are regular polygon and are vertex-transitive, although they aren't face-transitive. The solids were named after Archimedes, although he did not claim credit for them. They ...
to tessellate space.
* The
dodecagonal prism, which is the largest
prism that can tessellate space alongside other uniform prisms, has 14 faces.
* The
Szilassi polyhedron and its dual, the
Császár polyhedron, are the simplest
toroidal polyhedra
In geometry, a toroidal polyhedron is a polyhedron which is also a toroid (a -holed torus), having a topology (Mathematics), topological Genus (mathematics), genus () of 1 or greater. Notable examples include the Császár polyhedron, Császár a ...
; they have 14 vertices and 14 triangular faces, respectively.
*
Steffen's polyhedron, the simplest
flexible polyhedron without self-crossings, has 14 triangular faces.
A regular
tetrahedron
In geometry, a tetrahedron (: tetrahedra or tetrahedrons), also known as a triangular pyramid, is a polyhedron composed of four triangular Face (geometry), faces, six straight Edge (geometry), edges, and four vertex (geometry), vertices. The tet ...
cell, the simplest
uniform polyhedron
In geometry, a uniform polyhedron has regular polygons as Face (geometry), faces and is vertex-transitive—there is an isometry mapping any vertex onto any other. It follows that all vertices are congruence (geometry), congruent. Uniform po ...
and
Platonic solid
In geometry, a Platonic solid is a Convex polytope, convex, regular polyhedron in three-dimensional space, three-dimensional Euclidean space. Being a regular polyhedron means that the face (geometry), faces are congruence (geometry), congruent (id ...
, is made up of a total of 14
elements: 4
edges, 6 vertices, and 4 faces.
* Szilassi's polyhedron and the tetrahedron are the only two known polyhedra where each face shares an edge with each other face, while Császár's polyhedron and the tetrahedron are the only two known polyhedra with a continuous
manifold
In mathematics, a manifold is a topological space that locally resembles Euclidean space near each point. More precisely, an n-dimensional manifold, or ''n-manifold'' for short, is a topological space with the property that each point has a N ...
boundary that do not contain any
diagonal
In geometry, a diagonal is a line segment joining two vertices of a polygon or polyhedron, when those vertices are not on the same edge. Informally, any sloping line is called diagonal. The word ''diagonal'' derives from the ancient Greek � ...
s.
* Two tetrahedra that are joined by a common edge whose four adjacent and opposite faces are replaced with two specific seven-faced ''crinkles'' will create a new flexible polyhedron, with a total of 14 possible ''clashes'' where faces can meet.
pp.10-11,14 This is the second simplest known triangular flexible polyhedron, after Steffen's polyhedron.
p.16 If three tetrahedra are joined at two separate opposing edges and made into a single flexible polyhedron, called a ''2-dof flexible polyhedron'', each hinge will only have a total range of motion of 14 degrees.
p.139
14 is also the root (non-unitary) trivial
stella octangula number, where two
self-dual tetrahedra are represented through
figurate numbers, while also being the first non-trivial
square pyramidal number (after
5); the simplest of the ninety-two
Johnson solid
In geometry, a Johnson solid, sometimes also known as a Johnson–Zalgaller solid, is a convex polyhedron whose faces are regular polygons. They are sometimes defined to exclude the uniform polyhedrons. There are ninety-two Solid geometry, s ...
s is the
square pyramid
In geometry, a square pyramid is a Pyramid (geometry), pyramid with a square base and four triangles, having a total of five faces. If the Apex (geometry), apex of the pyramid is directly above the center of the square, it is a ''right square p ...
There are a total of fourteen
semi-regular polyhedra, when the
pseudorhombicuboctahedron is included as a non-
vertex transitive Archimedean solid
The Archimedean solids are a set of thirteen convex polyhedra whose faces are regular polygon and are vertex-transitive, although they aren't face-transitive. The solids were named after Archimedes, although he did not claim credit for them. They ...
(a lower class of polyhedra that follow the five Platonic solids).
Fourteen possible
Bravais lattices exist that fill three-dimensional space.
G2
The
exceptional Lie algebra G2 is the simplest of five such algebras, with a minimal
faithful representation In mathematics, especially in an area of abstract algebra known as representation theory, a faithful representation ρ of a group (mathematics), group on a vector space is a linear representation in which different elements of are represented by ...
in fourteen dimensions. It is the
automorphism group
In mathematics, the automorphism group of an object ''X'' is the group consisting of automorphisms of ''X'' under composition of morphisms. For example, if ''X'' is a finite-dimensional vector space, then the automorphism group of ''X'' is the g ...
of the
octonions , and holds a compact form
homeomorphic
In mathematics and more specifically in topology, a homeomorphism ( from Greek roots meaning "similar shape", named by Henri Poincaré), also called topological isomorphism, or bicontinuous function, is a bijective and continuous function betw ...
to the
zero divisor
In abstract algebra, an element of a ring is called a left zero divisor if there exists a nonzero in such that , or equivalently if the map from to that sends to is not injective. Similarly, an element of a ring is called a right ze ...
s with entries of
unit norm in the
sedenion
In abstract algebra, the sedenions form a 16-dimension of a vector space, dimensional commutative property, noncommutative and associative property, nonassociative algebra over a field, algebra over the real numbers, usually represented by the cap ...
s,
.
Riemann zeta function
The
floor
A floor is the bottom surface of a room or vehicle. Floors vary from wikt:hovel, simple dirt in a cave to many layered surfaces made with modern technology. Floors may be stone, wood, bamboo, metal or any other material that can support the ex ...
of the
imaginary part
In mathematics, a complex number is an element of a number system that extends the real numbers with a specific element denoted , called the imaginary unit and satisfying the equation i^= -1; every complex number can be expressed in the form ...
of the first non-trivial zero in the
Riemann zeta function
The Riemann zeta function or Euler–Riemann zeta function, denoted by the Greek letter (zeta), is a mathematical function of a complex variable defined as \zeta(s) = \sum_^\infty \frac = \frac + \frac + \frac + \cdots for and its analytic c ...
is
, in equivalence with its
nearest integer value, from an approximation of
In religion and mythology
Christianity
There is a fourteen-point silver star marking the traditional spot of Jesus’
birth
Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiated by hormones which cause the muscular walls of the uterus to contract, expelling the f ...
in the
Basilica of the Nativity in
Bethlehem
Bethlehem is a city in the West Bank, Palestine, located about south of Jerusalem, and the capital of the Bethlehem Governorate. It had a population of people, as of . The city's economy is strongly linked to Tourism in the State of Palesti ...
. According to the
genealogy of Jesus
The New Testament provides two accounts of the genealogy of Jesus, one in the Gospel of Matthew and another in the Gospel of Luke. Matthew starts with Abraham and works forwards, while Luke works back in time from Jesus to Adam. The lists of na ...
in the
Gospel of Matthew
The Gospel of Matthew is the first book of the New Testament of the Bible and one of the three synoptic Gospels. It tells the story of who the author believes is Israel's messiah (Christ (title), Christ), Jesus, resurrection of Jesus, his res ...
, “…there were fourteen generations in all from
Abraham
Abraham (originally Abram) is the common Hebrews, Hebrew Patriarchs (Bible), patriarch of the Abrahamic religions, including Judaism, Christianity, and Islam. In Judaism, he is the founding father who began the Covenant (biblical), covenanta ...
to
David
David (; , "beloved one") was a king of ancient Israel and Judah and the third king of the United Monarchy, according to the Hebrew Bible and Old Testament.
The Tel Dan stele, an Aramaic-inscribed stone erected by a king of Aram-Dam ...
, fourteen generations from David to the
exile to Babylon, and fourteen from the exile to the
Messiah
In Abrahamic religions, a messiah or messias (; ,
; ,
; ) is a saviour or liberator of a group of people. The concepts of '' mashiach'', messianism, and of a Messianic Age originated in Judaism, and in the Hebrew Bible, in which a ''mashiach ...
” (
Matthew 1:17).
Islam
In Islam, 14 has a special significance because of
the Fourteen Infallibles
The Fourteen Infallibles (, '; , ') in Twelver, Twelver Shia Islam are the Islamic prophet Muhammad, his daughter Fatima Zahra, Fatima, and Twelve Imams, the Twelve Imams. All are considered to be ismah, infallible under the theological conce ...
who are especially revered and important in
Twelver Shi'ism
Twelver Shi'ism (), also known as Imamism () or Ithna Ashari, is the largest branch of Shi'a Islam, comprising about 90% of all Shi'a Muslims. The term ''Twelver'' refers to its adherents' belief in twelve divinely ordained leaders, known as ...
. They are all considered to be infallible by Twelvers alongside
the Prophets of Islam, however these fourteen are said to have a greater significance and closeness to
God.
These fourteen include:
#
Prophet Muhammad (SAWA)
# His daughter,
Lady Fatima (SA)
# Her husband,
Imam Ali (AS)
# His son,
Imam Hasan (AS)
# His brother,
Imam Husayn (AS)
# His son,
Imam Ali al-Sajjad (AS)
# His son,
Imam Muhammad al-Baqir (AS)
# His son,
Imam Ja'far al-Sadiq (AS)
# His son,
Imam Musa al-Kazim (AS)
# His son,
Imam Ali al-Rida (AS)
# His son,
Imam Muhammad al-Jawad (AS)
# His son,
Imam Ali al-Hadi (AS)
# His son,
Imam Hasan al-Askari (AS)
# His son,
Imam Muhammad al-Mahdi (AJTFS)
Mythology
The number 14 was linked to
Šumugan and
Nergal
Nergal ( Sumerian: d''KIŠ.UNU'' or ; ; Aramaic: ܢܸܪܓܲܠ; ) was a Mesopotamian god worshiped through all periods of Mesopotamian history, from Early Dynastic to Neo-Babylonian times, with a few attestations indicating that his cult surv ...
.
In other fields
Fourteen is:
* The number of days in a
fortnight
A fortnight is a unit of time equal to 14 days (two weeks). The word derives from the Old English term , meaning "" (or "fourteen days", since the Anglo-Saxons counted by nights).
Astronomy and tides
In astronomy, a ''lunar fortnight'' is hal ...
.
Notes
References
Bibliography
*
{{Integers, zero
Integers