255689 has 4 divisors (see below), whose sum is σ = 292224. Its totient is φ = 219156.

The previous prime is 255679. The next prime is 255709. The reversal of 255689 is 986552.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a de Polignac number, because none of the positive numbers 2^k-255689 is a prime.

It is a Duffinian number.

It is a plaindrome in base 10.

It is a nialpdrome in base 8.

It is not an unprimeable number, because it can be changed into a prime (255649) 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, 18257 + ... + 18270.

It is an arithmetic number, because the mean of its divisors is an integer number (73056).

2²⁵⁵⁶⁸⁹ is an apocalyptic number.

It is an amenable number.

255689 is a deficient number, since it is larger than the sum of its proper divisors (36535).

255689 is an equidigital number, since it uses as much as digits as its factorization.

255689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36534.

The product of its digits is 21600, while the sum is 35.

The square root of 255689 is about 505.6569983694. The cubic root of 255689 is about 63.4703190695.

The spelling of 255689 in words is "two hundred fifty-five thousand, six hundred eighty-nine".