664221928 has 32 divisors (see below), whose sum is σ = 1280885760. Its totient is φ = 322678080.

The previous prime is 664221913. The next prime is 664221937. The reversal of 664221928 is 829122466.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 313593 + ... + 315703.

It is an arithmetic number, because the mean of its divisors is an integer number (40027680).

Almost surely, 2^664221928 is an apocalyptic number.

It is an amenable number.

664221928 is a deficient number, since it is larger than the sum of its proper divisors (616663832).

664221928 is a wasteful number, since it uses less digits than its factorization.

664221928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3217 (or 3213 counting only the distinct ones).

The product of its digits is 82944, while the sum is 40.

The square root of 664221928 is about 25772.5033320397. The cubic root of 664221928 is about 872.5113188079.

The spelling of 664221928 in words is "six hundred sixty-four million, two hundred twenty-one thousand, nine hundred twenty-eight".