720 (seven hundred
ndtwenty) is the
natural number
In mathematics, the natural numbers are those numbers used for counting (as in "there are ''six'' coins on the table") and ordering (as in "this is the ''third'' largest city in the country").
Numbers used for counting are called ''Cardinal n ...
following
719
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Year 719 ( DCCXIX) was a common year starting on Sunday (link will display the full calendar) of the Julian calendar. The denomination 719 for this year has been used since the early medieval period, when the Anno Domini calendar era ...
and preceding
721
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Year 721 (Roman numerals, DCCXXI) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar. The denomination 721 for this year has been used since the early medieval period, when the Anno ...
.
It is 6! (
6 factorial
In mathematics, the factorial of a non-negative denoted is the product of all positive integers less than or equal The factorial also equals the product of n with the next smaller factorial:
\begin
n! &= n \times (n-1) \times (n-2) \t ...
), a
composite number
A composite number is a positive integer that can be formed by multiplying two smaller positive integers. Equivalently, it is a positive integer that has at least one divisor other than 1 and itself. Every positive integer is composite, prime, ...
with thirty
divisor
In mathematics, a divisor of an integer n, also called a factor of n, is an integer m that may be multiplied by some integer to produce n. In this case, one also says that n is a multiple of m. An integer n is divisible or evenly divisible by ...
s, more than any number below, making it a
highly composite number
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A highly composite number is a positive integer with more divisors than any smaller positive integer has. The related concept of largely composite number refers to a positive integer which has at least as many divisors as any smaller ...
. It is a
Harshad number
In mathematics, a harshad number (or Niven number) in a given number base is an integer that is divisible by the sum of its digits when written in that base.
Harshad numbers in base are also known as -harshad (or -Niven) numbers.
Harshad numbers ...
in every base from binary to decimal.
720 is expressible as the product of consecutive integers in two different ways: , and .
[
]
There are 49 solutions to the equation
φ(''x'') = 720, more than any integer below it, making 720 a
highly totient number A highly totient number k is an integer that has more solutions to the equation \phi(x) = k, where \phi is Euler's totient function, than any integer below it. The first few highly totient numbers are
1, 2, 4, 8, 12, 24, 48, 72, 144, 240, ...
.
720 is a 241-
gonal number.
In other fields
720 is:
* A common vertical
display resolution
The display resolution or display modes of a digital television, computer monitor or display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is ...
for
HDTV
High-definition television (HD or HDTV) describes a television system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since 1936; in more recent times, it refers to the g ...
(see
720p
720p (1280×720 px; also called HD ready, standard HD or just HD) is a progressive HDTV signal format with 720 horizontal lines/1280 columns and an aspect ratio (AR) of 16:9, normally known as widescreen HDTV (1.78:1). All major HDTV broadcast ...
).
* 720° is two full rotations; the term "720" refers to a
skateboarding trick
A skateboarding trick, or simply a trick, is a maneuver performed by manipulating a skateboard, usually with one's feet, in a specific way to achieve the desired outcome – the trick.
History
Though skateboards emerged in the 1900s, skateboard ...
.
*
720°
''720°'' is a skateboarding video game released in arcades by Atari Games in 1986, in which the player controls a skateboarder skating around a middle-class neighborhood. By doing jumps and tricks, the player can eventually acquire enough poin ...
is also the name of a skateboarding video game.
* 720 is a dual
area code
A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the addresses of participants in a telephone network, rea ...
in the
Denver
Denver () is a consolidated city and county, the capital, and most populous city of the U.S. state of Colorado. Its population was 715,522 at the 2020 census, a 19.22% increase since 2010. It is the 19th-most populous city in the Unit ...
Metro Area along with 303.
* 720° is the sum of all the
defects of any
polyhedron
In geometry, a polyhedron (plural polyhedra or polyhedrons; ) is a three-dimensional shape with flat polygonal faces, straight edges and sharp corners or vertices.
A convex polyhedron is the convex hull of finitely many points, not all on th ...
.
* 720 is a short form of saying
Boeing 720
The Boeing 720 is an American narrow-body airliner produced by Boeing Commercial Airplanes.
Announced in July 1957 as a 707 derivative for shorter flights from shorter runways, the 720 first flew on November 23, 1959.
Its type certificate was ...
, an airliner which is no longer in service.
For the year AD, see
720
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Year 720 ( DCCXX) was a leap year starting on Monday (link will display the full calendar) of the Julian calendar. The denomination 720 for this year has been used since the early medieval period, when the Anno Domini calendar era ...
.
References
{{DEFAULTSORT:720 (Number)
Integers