664388631 has 12 divisors (see below), whose sum is σ = 962094952. Its totient is φ = 441807696.

The previous prime is 664388623. The next prime is 664388633. The reversal of 664388631 is 136883466.

664388631 is a `hidden beast` number, since 6 + 6 + 4 + 3 + 8 + 8 + 631 = 666.

664388631 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 664388631 - 2³ = 664388623 is a prime.

It is a super-2 number, since 2×664388631² = 882824506004108322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664388633) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 89401 + ... + 96546.

Almost surely, 2^664388631 is an apocalyptic number.

664388631 is a deficient number, since it is larger than the sum of its proper divisors (297706321).

664388631 is a wasteful number, since it uses less digits than its factorization.

664388631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186350 (or 186347 counting only the distinct ones).

The product of its digits is 497664, while the sum is 45.

The square root of 664388631 is about 25775.7372542475. The cubic root of 664388631 is about 872.5843055019.

The spelling of 664388631 in words is "six hundred sixty-four million, three hundred eighty-eight thousand, six hundred thirty-one".