255621 has 8 divisors (see below), whose sum is σ = 343840. Its totient is φ = 168912.

The previous prime is 255617. The next prime is 255637. The reversal of 255621 is 126552.

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

It is not a de Polignac number, because 255621 - 2² = 255617 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 255621.

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 7 ways as a sum of consecutive naturals, for example, 111 + ... + 723.

It is an arithmetic number, because the mean of its divisors is an integer number (42980).

2²⁵⁵⁶²¹ is an apocalyptic number.

It is an amenable number.

255621 is a deficient number, since it is larger than the sum of its proper divisors (88219).

255621 is a wasteful number, since it uses less digits than its factorization.

255621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 755.

The product of its digits is 600, while the sum is 21.

The square root of 255621 is about 505.5897546430. The cubic root of 255621 is about 63.4646919673.

The spelling of 255621 in words is "two hundred fifty-five thousand, six hundred twenty-one".