255865 has 8 divisors (see below), whose sum is σ = 311688. Its totient is φ = 201600.

The previous prime is 255859. The next prime is 255869. The reversal of 255865 is 568552.

It can be written as a sum of positive squares in 4 ways, for example, as 71824 + 184041 = 268^2 + 429^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 255865 - 2¹⁷ = 124793 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (255869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15 + ... + 715.

It is an arithmetic number, because the mean of its divisors is an integer number (38961).

2²⁵⁵⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

255865 is a deficient number, since it is larger than the sum of its proper divisors (55823).

255865 is an equidigital number, since it uses as much as digits as its factorization.

255865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 779.

The product of its digits is 12000, while the sum is 31.

The square root of 255865 is about 505.8309994455. The cubic root of 255865 is about 63.4848787025.

The spelling of 255865 in words is "two hundred fifty-five thousand, eight hundred sixty-five".