664445664 has 36 divisors (see below), whose sum is σ = 1889518176. Its totient is φ = 221481792.

The previous prime is 664445657. The next prime is 664445681. The reversal of 664445664 is 466544466.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1153264 + ... + 1153839.

It is an arithmetic number, because the mean of its divisors is an integer number (52486616).

Almost surely, 2^664445664 is an apocalyptic number.

It is an amenable number.

664445664 is an abundant number, since it is smaller than the sum of its proper divisors (1225072512).

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

664445664 is a wasteful number, since it uses less digits than its factorization.

664445664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2307119 (or 2307108 counting only the distinct ones).

The product of its digits is 1658880, while the sum is 45.

The square root of 664445664 is about 25776.8435616155. The cubic root of 664445664 is about 872.6092731561.

The spelling of 664445664 in words is "six hundred sixty-four million, four hundred forty-five thousand, six hundred sixty-four".