256617 has 6 divisors (see below), whose sum is σ = 370682. Its totient is φ = 171072.

The previous prime is 256609. The next prime is 256639. The reversal of 256617 is 716652.

It can be written as a sum of positive squares in only one way, i.e., 254016 + 2601 = 504^2 + 51^2 .

It is not a de Polignac number, because 256617 - 2³ = 256609 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 256617.

It is not an unprimeable number, because it can be changed into a prime (256687) 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 5 ways as a sum of consecutive naturals, for example, 14248 + ... + 14265.

2²⁵⁶⁶¹⁷ is an apocalyptic number.

It is an amenable number.

256617 is a deficient number, since it is larger than the sum of its proper divisors (114065).

256617 is a wasteful number, since it uses less digits than its factorization.

256617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28519 (or 28516 counting only the distinct ones).

The product of its digits is 2520, while the sum is 27.

The square root of 256617 is about 506.5737853462. The cubic root of 256617 is about 63.5470129456.

The spelling of 256617 in words is "two hundred fifty-six thousand, six hundred seventeen".