664640656 has 20 divisors (see below), whose sum is σ = 1305880704. Its totient is φ = 327639200.

The previous prime is 664640633. The next prime is 664640659. The reversal of 664640656 is 656046466.

664640656 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×664640656² = 883494403216220672, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (664640659) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 291400 + ... + 293671.

Almost surely, 2^664640656 is an apocalyptic number.

It is an amenable number.

664640656 is a deficient number, since it is larger than the sum of its proper divisors (641240048).

664640656 is a wasteful number, since it uses less digits than its factorization.

664640656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 585150 (or 585144 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 43.

The square root of 664640656 is about 25780.6255936507. The cubic root of 664640656 is about 872.6946250992.

The spelling of 664640656 in words is "six hundred sixty-four million, six hundred forty thousand, six hundred fifty-six".