665646664 has 16 divisors (see below), whose sum is σ = 1262112300. Its totient is φ = 329083392.

The previous prime is 665646643. The next prime is 665646677. The reversal of 665646664 is 466646566.

It can be written as a sum of positive squares in 2 ways, for example, as 656896900 + 8749764 = 25630^2 + 2958^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 466737 + ... + 468160.

Almost surely, 2^665646664 is an apocalyptic number.

It is an amenable number.

665646664 is a deficient number, since it is larger than the sum of its proper divisors (596465636).

665646664 is a wasteful number, since it uses less digits than its factorization.

665646664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 934992 (or 934988 counting only the distinct ones).

The product of its digits is 3732480, while the sum is 49.

The square root of 665646664 is about 25800.1291469636. The cubic root of 665646664 is about 873.1347101217.

The spelling of 665646664 in words is "six hundred sixty-five million, six hundred forty-six thousand, six hundred sixty-four".