256404 has 24 divisors (see below), whose sum is σ = 624960. Its totient is φ = 81664.

The previous prime is 256393. The next prime is 256423. The reversal of 256404 is 404652.

It is a happy number.

It is a super-2 number, since 2×256404² = 131486022432, which contains 22 as substring.

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 256404.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 189 + ... + 740.

It is an arithmetic number, because the mean of its divisors is an integer number (26040).

2²⁵⁶⁴⁰⁴ is an apocalyptic number.

It is an amenable number.

256404 is an abundant number, since it is smaller than the sum of its proper divisors (368556).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

256404 is a wasteful number, since it uses less digits than its factorization.

256404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 959 (or 957 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 256404 is about 506.3635057940. The cubic root of 256404 is about 63.5294260873.

The spelling of 256404 in words is "two hundred fifty-six thousand, four hundred four".