256664 has 8 divisors (see below), whose sum is σ = 481260. Its totient is φ = 128328.

The previous prime is 256661. The next prime is 256687. The reversal of 256664 is 466652.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16034 + ... + 16049.

2²⁵⁶⁶⁶⁴ is an apocalyptic number.

It is an amenable number.

256664 is a deficient number, since it is larger than the sum of its proper divisors (224596).

256664 is a wasteful number, since it uses less digits than its factorization.

256664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32089 (or 32085 counting only the distinct ones).

The product of its digits is 8640, while the sum is 29.

The square root of 256664 is about 506.6201733054. The cubic root of 256664 is about 63.5508923032.

The spelling of 256664 in words is "two hundred fifty-six thousand, six hundred sixty-four".