639897976 has 16 divisors (see below), whose sum is σ = 1200130200. Its totient is φ = 319863264.

The previous prime is 639897967. The next prime is 639898013. The reversal of 639897976 is 679798936.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30195 + ... + 46813.

Almost surely, 2^639897976 is an apocalyptic number.

It is an amenable number.

639897976 is a deficient number, since it is larger than the sum of its proper divisors (560232224).

639897976 is a wasteful number, since it uses less digits than its factorization.

639897976 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21438 (or 21434 counting only the distinct ones).

The product of its digits is 30862944, while the sum is 64.

The square root of 639897976 is about 25296.2047746297. The cubic root of 639897976 is about 861.7280810699.

The spelling of 639897976 in words is "six hundred thirty-nine million, eight hundred ninety-seven thousand, nine hundred seventy-six".