256517 has 2 divisors, whose sum is σ = 256518. Its totient is φ = 256516.

The previous prime is 256499. The next prime is 256541. The reversal of 256517 is 715652.

256517 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 185761 + 70756 = 431^2 + 266^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256517 is a prime.

It is a zygodrome in base 4.

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 256517.

It is not a weakly prime, because it can be changed into another prime (256567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128258 + 128259.

It is an arithmetic number, because the mean of its divisors is an integer number (128259).

2²⁵⁶⁵¹⁷ is an apocalyptic number.

It is an amenable number.

256517 is a deficient number, since it is larger than the sum of its proper divisors (1).

256517 is an equidigital number, since it uses as much as digits as its factorization.

256517 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2100, while the sum is 26.

The square root of 256517 is about 506.4750734242. The cubic root of 256517 is about 63.5387574170.

The spelling of 256517 in words is "two hundred fifty-six thousand, five hundred seventeen".