180 (one hundred
ndeighty) 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
179 and preceding
181.
In mathematics
180 is an
abundant number
In number theory, an abundant number or excessive number is a number for which the sum of its proper divisors is greater than the number. The integer 12 is the first abundant number. Its proper divisors are 1, 2, 3, 4 and 6 for a total of 16. The ...
, with its proper divisors summing up to 366.
[
] 180 is also a
highly composite number
__FORCETOC__
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 ...
, a positive integer with more divisors than any smaller positive integer. One of the consequences of 180 having so many divisors is that it is a
practical number
In number theory, a practical number or panarithmic number is a positive integer n such that all smaller positive integers can be represented as sums of distinct divisors of n. For example, 12 is a practical number because all the numbers from 1 ...
, meaning that any positive number smaller than 180 that is not a divisor of 180 can be expressed as the sum of some of 180's divisors. 180 is a Harshad number and a
refactorable number
A refactorable number or tau number is an integer ''n'' that is divisible by the count of its divisors, or to put it algebraically, ''n'' is such that \tau(n)\mid n. The first few refactorable numbers are listed in as
: 1, 2, 8, 9, 12, 18, ...
.
180 is the
sum of two
square number
In mathematics, a square number or perfect square is an integer that is the square (algebra), square of an integer; in other words, it is the multiplication, product of some integer with itself. For example, 9 is a square number, since it equals ...
s: 12
2 + 6
2. It can be expressed as either the sum of six consecutive
prime number
A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways ...
s:
19 +
23 +
29 +
31 +
37 +
41, or the sum of eight consecutive
prime number
A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways ...
s:
11 +
13 +
17 +
19 +
23 +
29 +
31 +
37. 180 is an
Ulam number
In mathematics, the Ulam numbers comprise an integer sequence devised by and named after Stanislaw Ulam, who introduced it in 1964. The standard Ulam sequence (the (1, 2)-Ulam sequence) starts with ''U''1 = 1 and ''U''2 =&nbs ...
, which can be expressed as a sum of earlier terms in the Ulam sequence only as 177 + 3.
180 is a 61-
gonal number.
[
Half a ]circle
A circle is a shape consisting of all points in a plane that are at a given distance from a given point, the centre. Equivalently, it is the curve traced out by a point that moves in a plane so that its distance from a given point is const ...
has 180 degrees, and thus a U-turn
A U-turn in driving refers to performing a 180° rotation to reverse the direction of travel. It is called a "U-turn" because the maneuver looks like the letter U. In some areas, the maneuver is illegal, while in others, it is treated as a m ...
is also referred to as a ''180''.
Summing Euler's totient function
In number theory, Euler's totient function counts the positive integers up to a given integer that are relatively prime to . It is written using the Greek letter phi as \varphi(n) or \phi(n), and may also be called Euler's phi function. In ot ...
φ(''x'') over the first + 24 integers gives 180.
In binary
Binary may refer to:
Science and technology Mathematics
* Binary number, a representation of numbers using only two digits (0 and 1)
* Binary function, a function that takes two arguments
* Binary operation, a mathematical operation that t ...
it is a digitally balanced number, since its binary representation has the same number of zeros as ones (10110100).
In religion
The Book of Genesis
The Book of Genesis (from Greek ; Hebrew: בְּרֵאשִׁית ''Bəreʾšīt'', "In hebeginning") is the first book of the Hebrew Bible and the Christian Old Testament. Its Hebrew name is the same as its first word, ( "In the beginning") ...
says that Isaac
Isaac; grc, Ἰσαάκ, Isaák; ar, إسحٰق/إسحاق, Isḥāq; am, ይስሐቅ is one of the three patriarchs of the Israelites and an important figure in the Abrahamic religions, including Judaism, Christianity, and Islam. He was the ...
died at the age of 180.
Other
* All of the ''Final Destination
''Final Destination'' is an American horror franchise that includes five films, two comic books, and nine novels. It is based on an unproduced spec script by Jeffrey Reddick, originally written for ''The X-Files'' television series, and was d ...
'' series has used the number for death clues, starting off in the first film as a flight number to a 747 airliner based on TWA Flight 800
Trans World Airlines Flight 800 (TWA800) was a Boeing 747-100 that exploded and crashed into the Atlantic Ocean near East Moriches, New York, on July 17, 1996, at about 8:31pm. EDT, 12 minutes after takeoff from John F. Kennedy International ...
.
* 180 is the highest score possible with three darts.
See also
* List of highways numbered 180
* United Nations Security Council Resolution 180
* United States Supreme Court cases, Volume 180
* Pennsylvania House of Representatives, District 180
References
External links
*
*
{{DEFAULTSORT:180 (Number)
Integers