7978517689129 has 81 divisors (see below), whose sum is σ = 9195993393111. Its totient is φ = 6918754358880.

The previous prime is 7978517689049. The next prime is 7978517689147. The reversal of 7978517689129 is 9219867158797.

The square root of 7978517689129 is 2824627.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 1180254096025 + 6798263593104 = 1086395^2 + 2607348^2 .

It is not a de Polignac number, because 7978517689129 - 2¹⁹ = 7978517164841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7978547689129) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 48947961202 + ... + 48947961364.

It is an arithmetic number, because the mean of its divisors is an integer number (113530782631).

Almost surely, 2^{7978517689129} is an apocalyptic number.

7978517689129 is the 2824627-th square number.

7978517689129 is the 1412314-th centered octagonal number.

It is an amenable number.

7978517689129 is a deficient number, since it is larger than the sum of its proper divisors (1217475703982).

7978517689129 is an equidigital number, since it uses as much as digits as its factorization.

7978517689129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 500 (or 250 counting only the distinct ones).

The product of its digits is 960180480, while the sum is 79.

The spelling of 7978517689129 in words is "seven trillion, nine hundred seventy-eight billion, five hundred seventeen million, six hundred eighty-nine thousand, one hundred twenty-nine".