664857 has 12 divisors (see below), whose sum is σ = 991744. Its totient is φ = 428760.

The previous prime is 664849. The next prime is 664879. The reversal of 664857 is 758466.

It is a happy number.

664857 is a `hidden beast` number, since 6 + 648 + 5 + 7 = 666.

It is not a de Polignac number, because 664857 - 2³ = 664849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664847) 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, 913 + ... + 1470.

2⁶⁶⁴⁸⁵⁷ is an apocalyptic number.

It is an amenable number.

664857 is a deficient number, since it is larger than the sum of its proper divisors (326887).

664857 is a wasteful number, since it uses less digits than its factorization.

664857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2420 (or 2417 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 664857 is about 815.3876378754. The cubic root of 664857 is about 87.2789303711.

It can be divided in two parts, 664 and 857, that added together give a square (1521 = 39²).

The spelling of 664857 in words is "six hundred sixty-four thousand, eight hundred fifty-seven".