638765085256 has 16 divisors (see below), whose sum is σ = 1199088632700. Its totient is φ = 319008116544.

The previous prime is 638765085193. The next prime is 638765085341. The reversal of 638765085256 is 652580567836.

It can be written as a sum of positive squares in 2 ways, for example, as 460723282756 + 178041802500 = 678766^2 + 421950^2 .

It is a junction number, because it is equal to n+sod(n) for n = 638765085194 and 638765085203.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46796011 + ... + 46809658.

Almost surely, 2^638765085256 is an apocalyptic number.

It is an amenable number.

638765085256 is a deficient number, since it is larger than the sum of its proper divisors (560323547444).

638765085256 is a wasteful number, since it uses less digits than its factorization.

638765085256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93606528 (or 93606524 counting only the distinct ones).

The product of its (nonzero) digits is 72576000, while the sum is 61.

The spelling of 638765085256 in words is "six hundred thirty-eight billion, seven hundred sixty-five million, eighty-five thousand, two hundred fifty-six".