255861 has 6 divisors (see below), whose sum is σ = 369590. Its totient is φ = 170568.

The previous prime is 255859. The next prime is 255869. The reversal of 255861 is 168552.

255861 is nontrivially palindromic in base 13.

It can be written as a sum of positive squares in only one way, i.e., 202500 + 53361 = 450^2 + 231^2 .

It is not a de Polignac number, because 255861 - 2¹ = 255859 is a prime.

It is a Duffinian number.

It is a Curzon 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 5 ways as a sum of consecutive naturals, for example, 14206 + ... + 14223.

2²⁵⁵⁸⁶¹ is an apocalyptic number.

It is an amenable number.

255861 is a deficient number, since it is larger than the sum of its proper divisors (113729).

255861 is a wasteful number, since it uses less digits than its factorization.

255861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28435 (or 28432 counting only the distinct ones).

The product of its digits is 2400, while the sum is 27.

The square root of 255861 is about 505.8270455403. The cubic root of 255861 is about 63.4845478759.

It can be divided in two parts, 25 and 5861, that added together give a triangular number (5886 = T₁₀₈).

The spelling of 255861 in words is "two hundred fifty-five thousand, eight hundred sixty-one".