204565421 has 2 divisors, whose sum is σ = 204565422. Its totient is φ = 204565420.

The previous prime is 204565399. The next prime is 204565429. The reversal of 204565421 is 124565402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 114789796 + 89775625 = 10714^2 + 9475^2 .

It is a cyclic number.

It is not a de Polignac number, because 204565421 - 2⁶ = 204565357 is a prime.

It is a super-2 number, since 2×204565421² = 83694022937814482, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (204565429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102282710 + 102282711.

It is an arithmetic number, because the mean of its divisors is an integer number (102282711).

Almost surely, 2^204565421 is an apocalyptic number.

It is an amenable number.

204565421 is a deficient number, since it is larger than the sum of its proper divisors (1).

204565421 is an equidigital number, since it uses as much as digits as its factorization.

204565421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9600, while the sum is 29.

The square root of 204565421 is about 14302.6368547901. The cubic root of 204565421 is about 589.2199026505.

The spelling of 204565421 in words is "two hundred four million, five hundred sixty-five thousand, four hundred twenty-one".