255821621 has 8 divisors (see below), whose sum is σ = 279332064. Its totient is φ = 232353520.

The previous prime is 255821597. The next prime is 255821623. The reversal of 255821621 is 126128552.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-255821621 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (255821623) 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, 2795 + ... + 22791.

It is an arithmetic number, because the mean of its divisors is an integer number (34916508).

Almost surely, 2^255821621 is an apocalyptic number.

It is an amenable number.

255821621 is a deficient number, since it is larger than the sum of its proper divisors (23510443).

255821621 is a wasteful number, since it uses less digits than its factorization.

255821621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21171.

The product of its digits is 9600, while the sum is 32.

The square root of 255821621 is about 15994.4246848707. The cubic root of 255821621 is about 634.8129078678.

The spelling of 255821621 in words is "two hundred fifty-five million, eight hundred twenty-one thousand, six hundred twenty-one".