256864 has 24 divisors (see below), whose sum is σ = 529200. Its totient is φ = 122496.

The previous prime is 256831. The next prime is 256873. The reversal of 256864 is 468652.

256864 is nontrivially palindromic in base 3.

It is a super-2 number, since 2×256864² = 131958228992, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors.

256864 is a modest number, since divided by 864 gives 256 as remainder.

It is a nialpdrome in base 8.

It is a zygodrome in base 3.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 562 + ... + 910.

It is an arithmetic number, because the mean of its divisors is an integer number (22050).

2²⁵⁶⁸⁶⁴ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 256864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (264600).

256864 is an abundant number, since it is smaller than the sum of its proper divisors (272336).

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

256864 is a wasteful number, since it uses less digits than its factorization.

256864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 382 (or 374 counting only the distinct ones).

The product of its digits is 11520, while the sum is 31.

The square root of 256864 is about 506.8175214019. The cubic root of 256864 is about 63.5673949142.

It can be divided in two parts, 25 and 6864, that added together give a square (6889 = 83²).

The spelling of 256864 in words is "two hundred fifty-six thousand, eight hundred sixty-four".