256915 has 4 divisors (see below), whose sum is σ = 308304. Its totient is φ = 205528.

The previous prime is 256903. The next prime is 256931. The reversal of 256915 is 519652.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 256915 - 2¹³ = 248723 is a prime.

It is a Duffinian 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, 25687 + ... + 25696.

It is an arithmetic number, because the mean of its divisors is an integer number (77076).

2²⁵⁶⁹¹⁵ is an apocalyptic number.

256915 is a deficient number, since it is larger than the sum of its proper divisors (51389).

256915 is an equidigital number, since it uses as much as digits as its factorization.

256915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51388.

The product of its digits is 2700, while the sum is 28.

The square root of 256915 is about 506.8678328716. The cubic root of 256915 is about 63.5716017093.

The spelling of 256915 in words is "two hundred fifty-six thousand, nine hundred fifteen".