664563321 has 24 divisors (see below), whose sum is σ = 974413440. Its totient is φ = 436388256.

The previous prime is 664563293. The next prime is 664563359. The reversal of 664563321 is 123365466.

664563321 is a `hidden beast` number, since 6 + 64 + 563 + 32 + 1 = 666.

It is not a de Polignac number, because 664563321 - 2⁶ = 664563257 is a prime.

It is not an unprimeable number, because it can be changed into a prime (664563121) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 289440 + ... + 291726.

It is an arithmetic number, because the mean of its divisors is an integer number (40600560).

Almost surely, 2^664563321 is an apocalyptic number.

It is an amenable number.

664563321 is a deficient number, since it is larger than the sum of its proper divisors (309850119).

664563321 is a wasteful number, since it uses less digits than its factorization.

664563321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2765 (or 2762 counting only the distinct ones).

The product of its digits is 77760, while the sum is 36.

The square root of 664563321 is about 25779.1256833897. The cubic root of 664563321 is about 872.6607760030.

The spelling of 664563321 in words is "six hundred sixty-four million, five hundred sixty-three thousand, three hundred twenty-one".