664776320 has 64 divisors (see below), whose sum is σ = 1711500840. Its totient is φ = 245452800.

The previous prime is 664776311. The next prime is 664776323. The reversal of 664776320 is 23677466.

It can be written as a sum of positive squares in 4 ways, for example, as 359785024 + 304991296 = 18968^2 + 17464^2 .

It is a tau number, because it is divible by the number of its divisors (64).

It is not an unprimeable number, because it can be changed into a prime (664776323) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31631 + ... + 48270.

Almost surely, 2^664776320 is an apocalyptic number.

It is an amenable number.

664776320 is an abundant number, since it is smaller than the sum of its proper divisors (1046724520).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

664776320 is a wasteful number, since it uses less digits than its factorization.

664776320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79933 (or 79921 counting only the distinct ones).

The product of its (nonzero) digits is 254016, while the sum is 41.

The square root of 664776320 is about 25783.2565825188. The cubic root of 664776320 is about 872.7539981294.

The spelling of 664776320 in words is "six hundred sixty-four million, seven hundred seventy-six thousand, three hundred twenty".