255985 has 4 divisors (see below), whose sum is σ = 307188. Its totient is φ = 204784.

The previous prime is 255977. The next prime is 255989. The reversal of 255985 is 589552.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 194481 + 61504 = 441^2 + 248^2 .

It is a cyclic number.

It is not a de Polignac number, because 255985 - 2³ = 255977 is a prime.

It is a Duffinian number.

255985 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 255985.

It is not an unprimeable number, because it can be changed into a prime (255989) 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 3 ways as a sum of consecutive naturals, for example, 25594 + ... + 25603.

It is an arithmetic number, because the mean of its divisors is an integer number (76797).

2²⁵⁵⁹⁸⁵ is an apocalyptic number.

It is an amenable number.

255985 is a deficient number, since it is larger than the sum of its proper divisors (51203).

255985 is an equidigital number, since it uses as much as digits as its factorization.

255985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51202.

The product of its digits is 18000, while the sum is 34.

The square root of 255985 is about 505.9496022333. The cubic root of 255985 is about 63.4948018974.

The spelling of 255985 in words is "two hundred fifty-five thousand, nine hundred eighty-five".