639394688 has 32 divisors (see below), whose sum is σ = 1340841000. Its totient is φ = 302870016.

The previous prime is 639394673. The next prime is 639394711. The reversal of 639394688 is 886493936.

It is a tau number, because it is divible by the number of its divisors (32).

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, 129023 + ... + 133886.

Almost surely, 2^639394688 is an apocalyptic number.

It is an amenable number.

639394688 is an abundant number, since it is smaller than the sum of its proper divisors (701446312).

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

639394688 is a wasteful number, since it uses less digits than its factorization.

639394688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 262942 (or 262930 counting only the distinct ones).

The product of its digits is 6718464, while the sum is 56.

The square root of 639394688 is about 25286.2549223882. The cubic root of 639394688 is about 861.5021017361.

The spelling of 639394688 in words is "six hundred thirty-nine million, three hundred ninety-four thousand, six hundred eighty-eight".