256917 has 4 divisors (see below), whose sum is σ = 342560. Its totient is φ = 171276.

The previous prime is 256903. The next prime is 256931. The reversal of 256917 is 719652.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (256903) and next prime (256931).

It is not a de Polignac number, because 256917 - 2⁴ = 256901 is a prime.

It is a D-number.

It is a Duffinian number.

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 256917.

It is not an unprimeable number, because it can be changed into a prime (256957) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42817 + ... + 42822.

It is an arithmetic number, because the mean of its divisors is an integer number (85640).

2²⁵⁶⁹¹⁷ is an apocalyptic number.

It is an amenable number.

256917 is a deficient number, since it is larger than the sum of its proper divisors (85643).

256917 is an equidigital number, since it uses as much as digits as its factorization.

256917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85642.

The product of its digits is 3780, while the sum is 30.

The square root of 256917 is about 506.8698057687. The cubic root of 256917 is about 63.5717666703.

The spelling of 256917 in words is "two hundred fifty-six thousand, nine hundred seventeen".