638403257264 has 20 divisors (see below), whose sum is σ = 1236959653920. Its totient is φ = 319187862720.

The previous prime is 638403257249. The next prime is 638403257279. The reversal of 638403257264 is 462752304836.

It is an interprime number because it is at equal distance from previous prime (638403257249) and next prime (638403257279).

It is a hoax number, since the sum of its digits (50) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 472472 + ... + 1224759.

It is an arithmetic number, because the mean of its divisors is an integer number (61847982696).

Almost surely, 2^638403257264 is an apocalyptic number.

It is an amenable number.

638403257264 is a deficient number, since it is larger than the sum of its proper divisors (598556396656).

638403257264 is a wasteful number, since it uses less digits than its factorization.

638403257264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1720748 (or 1720742 counting only the distinct ones).

The product of its (nonzero) digits is 5806080, while the sum is 50.

The spelling of 638403257264 in words is "six hundred thirty-eight billion, four hundred three million, two hundred fifty-seven thousand, two hundred sixty-four".