256817 has 8 divisors (see below), whose sum is σ = 288192. Its totient is φ = 226800.

The previous prime is 256813. The next prime is 256831. The reversal of 256817 is 718652.

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 256817 - 2² = 256813 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 256817.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 256817.

It is not an unprimeable number, because it can be changed into a prime (256813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 92 + ... + 722.

It is an arithmetic number, because the mean of its divisors is an integer number (36024).

2²⁵⁶⁸¹⁷ is an apocalyptic number.

It is an amenable number.

256817 is a deficient number, since it is larger than the sum of its proper divisors (31375).

256817 is a wasteful number, since it uses less digits than its factorization.

256817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 679.

The product of its digits is 3360, while the sum is 29.

The square root of 256817 is about 506.7711515073. The cubic root of 256817 is about 63.5635175708.

The spelling of 256817 in words is "two hundred fifty-six thousand, eight hundred seventeen".