204621 has 4 divisors (see below), whose sum is σ = 272832. Its totient is φ = 136412.

The previous prime is 204613. The next prime is 204623. The reversal of 204621 is 126402.

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 cyclic number.

It is not a de Polignac number, because 204621 - 2³ = 204613 is a prime.

It is a D-number.

It is a self number, because there is not a number n which added to its sum of digits gives 204621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204623) 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, 34101 + ... + 34106.

It is an arithmetic number, because the mean of its divisors is an integer number (68208).

2²⁰⁴⁶²¹ is an apocalyptic number.

It is an amenable number.

204621 is a deficient number, since it is larger than the sum of its proper divisors (68211).

204621 is an equidigital number, since it uses as much as digits as its factorization.

204621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68210.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 204621 is about 452.3505277990. The cubic root of 204621 is about 58.9273260133.

The spelling of 204621 in words is "two hundred four thousand, six hundred twenty-one".