1980 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 1979 and preceding 1981.

Mathematics

1980 is a pronic number, a highly abundant number, an e-perfect number and a coreful perfect number. Not only is it highly abundant, but it also has a greater

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 ...

than any smaller number. 1980 is the fourth number with 36

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 divisibl ...

s. It forms an amicable triple with

2016 2016 was designated as: * International Year of Pulses by the sixty-eighth session of the United Nations General Assembly. * International Year of Global Understanding (IYGU) by the International Council for Science (ICSU), the Internationa ...

and 2556, since σ(1980) = σ(2016) = σ(2556) and 6552 = 1980 + 2016 + 2556.

References

Integers {{number-stub