255681 has 6 divisors (see below), whose sum is σ = 369330. Its totient is φ = 170448.

The previous prime is 255679. The next prime is 255709. The reversal of 255681 is 186552.

255681 = 84² + 85² + ... + 110².

It can be written as a sum of positive squares in only one way, i.e., 230400 + 25281 = 480^2 + 159^2 .

It is not a de Polignac number, because 255681 - 2¹ = 255679 is a prime.

It is a super-2 number, since 2×255681² = 130745547522, which contains 22 as substring.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 255681.

It is not an unprimeable number, because it can be changed into a prime (255641) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 14196 + ... + 14213.

It is an arithmetic number, because the mean of its divisors is an integer number (61555).

2²⁵⁵⁶⁸¹ is an apocalyptic number.

It is an amenable number.

255681 is a deficient number, since it is larger than the sum of its proper divisors (113649).

255681 is a wasteful number, since it uses less digits than its factorization.

255681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28415 (or 28412 counting only the distinct ones).

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

The square root of 255681 is about 505.6490878069. The cubic root of 255681 is about 63.4696571092.

The spelling of 255681 in words is "two hundred fifty-five thousand, six hundred eighty-one".