638456664 has 32 divisors (see below), whose sum is σ = 1598782320. Its totient is φ = 212466816.

The previous prime is 638456657. The next prime is 638456717. The reversal of 638456664 is 466654836.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6987 + ... + 36410.

Almost surely, 2^638456664 is an apocalyptic number.

It is an amenable number.

638456664 is an abundant number, since it is smaller than the sum of its proper divisors (960325656).

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

638456664 is a wasteful number, since it uses less digits than its factorization.

638456664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44019 (or 44015 counting only the distinct ones).

The product of its digits is 2488320, while the sum is 48.

The square root of 638456664 is about 25267.7000140496. The cubic root of 638456664 is about 861.0806066543.

The spelling of 638456664 in words is "six hundred thirty-eight million, four hundred fifty-six thousand, six hundred sixty-four".