204321621 has 12 divisors (see below), whose sum is σ = 316907232. Its totient is φ = 116755128.

The previous prime is 204321613. The next prime is 204321629. The reversal of 204321621 is 126123402.

It is an interprime number because it is at equal distance from previous prime (204321613) and next prime (204321629).

It is not a de Polignac number, because 204321621 - 2³ = 204321613 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204321629) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 694825 + ... + 695118.

It is an arithmetic number, because the mean of its divisors is an integer number (26408936).

Almost surely, 2^204321621 is an apocalyptic number.

204321621 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

204321621 is a deficient number, since it is larger than the sum of its proper divisors (112585611).

204321621 is a wasteful number, since it uses less digits than its factorization.

204321621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1389960 (or 1389953 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 204321621 is about 14294.1114099478. Note that the first 3 decimals coincide. The cubic root of 204321621 is about 588.9857331980.

The spelling of 204321621 in words is "two hundred four million, three hundred twenty-one thousand, six hundred twenty-one".