255817 has 4 divisors (see below), whose sum is σ = 256900. Its totient is φ = 254736.

The previous prime is 255803. The next prime is 255839. The reversal of 255817 is 718552.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 226576 + 29241 = 476^2 + 171^2 .

It is a cyclic number.

It is not a de Polignac number, because 255817 - 2¹¹ = 253769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (255847) 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 3 ways as a sum of consecutive naturals, for example, 18 + ... + 715.

It is an arithmetic number, because the mean of its divisors is an integer number (64225).

2²⁵⁵⁸¹⁷ is an apocalyptic number.

It is an amenable number.

255817 is a deficient number, since it is larger than the sum of its proper divisors (1083).

255817 is an equidigital number, since it uses as much as digits as its factorization.

255817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1082.

The product of its digits is 2800, while the sum is 28.

The square root of 255817 is about 505.7835505431. The cubic root of 255817 is about 63.4809085558.

It can be divided in two parts, 255 and 817, that multiplied together give a triangular number (208335 = T₆₄₅).

The spelling of 255817 in words is "two hundred fifty-five thousand, eight hundred seventeen".