646704665 has 16 divisors (see below), whose sum is σ = 787987200. Its totient is φ = 509438592.

The previous prime is 646704629. The next prime is 646704673. The reversal of 646704665 is 566407646.

It is a cyclic number.

It is not a de Polignac number, because 646704665 - 2⁶ = 646704601 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 159554 + ... + 163556.

It is an arithmetic number, because the mean of its divisors is an integer number (49249200).

Almost surely, 2^646704665 is an apocalyptic number.

It is an amenable number.

646704665 is a deficient number, since it is larger than the sum of its proper divisors (141282535).

646704665 is a wasteful number, since it uses less digits than its factorization.

646704665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4496.

The product of its (nonzero) digits is 725760, while the sum is 44.

The square root of 646704665 is about 25430.3886128388. The cubic root of 646704665 is about 864.7727537411.

The spelling of 646704665 in words is "six hundred forty-six million, seven hundred four thousand, six hundred sixty-five".