639963256 has 16 divisors (see below), whose sum is σ = 1238639040. Its totient is φ = 309659520.

The previous prime is 639963251. The next prime is 639963299. The reversal of 639963256 is 652369936.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639963251) by changing a digit.

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, 1290001 + ... + 1290496.

It is an arithmetic number, because the mean of its divisors is an integer number (77414940).

Almost surely, 2^639963256 is an apocalyptic number.

It is an amenable number.

639963256 is a deficient number, since it is larger than the sum of its proper divisors (598675784).

639963256 is a wasteful number, since it uses less digits than its factorization.

639963256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2580534 (or 2580530 counting only the distinct ones).

The product of its digits is 1574640, while the sum is 49.

The square root of 639963256 is about 25297.4950538586. The cubic root of 639963256 is about 861.7573834996.

The spelling of 639963256 in words is "six hundred thirty-nine million, nine hundred sixty-three thousand, two hundred fifty-six".