640990976 has 18 divisors (see below), whose sum is σ = 1279478592. Its totient is φ = 320495360.

The previous prime is 640990969. The next prime is 640990993. The reversal of 640990976 is 679099046.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1251680 + ... + 1252191.

It is an arithmetic number, because the mean of its divisors is an integer number (71082144).

Almost surely, 2^640990976 is an apocalyptic number.

It is an amenable number.

640990976 is a deficient number, since it is larger than the sum of its proper divisors (638487616).

640990976 is an equidigital number, since it uses as much as digits as its factorization.

640990976 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2503887 (or 2503873 counting only the distinct ones).

The product of its (nonzero) digits is 734832, while the sum is 50.

The square root of 640990976 is about 25317.7995884319. The cubic root of 640990976 is about 862.2184368622.

The spelling of 640990976 in words is "six hundred forty million, nine hundred ninety thousand, nine hundred seventy-six".