204665621 has 2 divisors, whose sum is σ = 204665622. Its totient is φ = 204665620.

The previous prime is 204665599. The next prime is 204665639. The reversal of 204665621 is 126566402.

204665621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 151536100 + 53129521 = 12310^2 + 7289^2 .

It is a cyclic number.

It is not a de Polignac number, because 204665621 - 2²² = 200471317 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (204661621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102332810 + 102332811.

It is an arithmetic number, because the mean of its divisors is an integer number (102332811).

Almost surely, 2^204665621 is an apocalyptic number.

It is an amenable number.

204665621 is a deficient number, since it is larger than the sum of its proper divisors (1).

204665621 is an equidigital number, since it uses as much as digits as its factorization.

204665621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 204665621 is about 14306.1392765484. The cubic root of 204665621 is about 589.3160906197.

The spelling of 204665621 in words is "two hundred four million, six hundred sixty-five thousand, six hundred twenty-one".