256891 has 8 divisors (see below), whose sum is σ = 270864. Its totient is φ = 243360.

The previous prime is 256889. The next prime is 256901. The reversal of 256891 is 198652.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 256891 - 2¹ = 256889 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256801) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1896 + ... + 2026.

It is an arithmetic number, because the mean of its divisors is an integer number (33858).

2²⁵⁶⁸⁹¹ is an apocalyptic number.

256891 is a deficient number, since it is larger than the sum of its proper divisors (13973).

256891 is a wasteful number, since it uses less digits than its factorization.

256891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221.

The product of its digits is 4320, while the sum is 31.

The square root of 256891 is about 506.8441575080. The cubic root of 256891 is about 63.5696221104.

The spelling of 256891 in words is "two hundred fifty-six thousand, eight hundred ninety-one".