638814261751056 has 480 divisors, whose sum is σ = 1912286675819520. Its totient is φ = 198377961062400.

The previous prime is 638814261751049. The next prime is 638814261751139. The reversal of 638814261751056 is 650157162418836.

It is a happy number.

638814261751056 is a `hidden beast` number, since 6 + 3 + 8 + 8 + 1 + 4 + 2 + 61 + 7 + 510 + 56 = 666.

It is a super-2 number, since 2×638814261751056² (a number of 30 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 638814261750984 and 638814261751002.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 164600426236 + ... + 164600430116.

It is an arithmetic number, because the mean of its divisors is an integer number (3983930574624).

Almost surely, 2^{638814261751056} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638814261751056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (956143337909760).

638814261751056 is an abundant number, since it is smaller than the sum of its proper divisors (1273472414068464).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

638814261751056 is a wasteful number, since it uses less digits than its factorization.

638814261751056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5775 (or 5766 counting only the distinct ones).

The product of its (nonzero) digits is 58060800, while the sum is 63.

The spelling of 638814261751056 in words is "six hundred thirty-eight trillion, eight hundred fourteen billion, two hundred sixty-one million, seven hundred fifty-one thousand, fifty-six".