664688 has 10 divisors (see below), whose sum is σ = 1287864. Its totient is φ = 332336.

The previous prime is 664687. The next prime is 664691. The reversal of 664688 is 886466.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 664688.

It is not an unprimeable number, because it can be changed into a prime (664687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20756 + ... + 20787.

2⁶⁶⁴⁶⁸⁸ is an apocalyptic number.

It is an amenable number.

664688 is a deficient number, since it is larger than the sum of its proper divisors (623176).

664688 is a wasteful number, since it uses less digits than its factorization.

664688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41551 (or 41545 counting only the distinct ones).

The product of its digits is 55296, while the sum is 38.

The square root of 664688 is about 815.2839995977. The cubic root of 664688 is about 87.2715346007.

The spelling of 664688 in words is "six hundred sixty-four thousand, six hundred eighty-eight".