664856 has 16 divisors (see below), whose sum is σ = 1277640. Its totient is φ = 324160.

The previous prime is 664849. The next prime is 664879. The reversal of 664856 is 658466.

It is a congruent number.

It is an unprimeable number.

664856 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 in 3 ways as a sum of consecutive naturals, for example, 686 + ... + 1341.

2⁶⁶⁴⁸⁵⁶ is an apocalyptic number.

It is an amenable number.

664856 is a deficient number, since it is larger than the sum of its proper divisors (612784).

664856 is a wasteful number, since it uses less digits than its factorization.

664856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2074 (or 2070 counting only the distinct ones).

The product of its digits is 34560, while the sum is 35.

The square root of 664856 is about 815.3870246699. The cubic root of 664856 is about 87.2788866128.

The spelling of 664856 in words is "six hundred sixty-four thousand, eight hundred fifty-six".