204564561 has 16 divisors (see below), whose sum is σ = 279474048. Its totient is φ = 133056000.

The previous prime is 204564541. The next prime is 204564589. The reversal of 204564561 is 165465402.

It is not a de Polignac number, because 204564561 - 2⁷ = 204564433 is a prime.

It is not an unprimeable number, because it can be changed into a prime (204564541) 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 15 ways as a sum of consecutive naturals, for example, 15711 + ... + 25611.

It is an arithmetic number, because the mean of its divisors is an integer number (17467128).

Almost surely, 2^204564561 is an apocalyptic number.

It is an amenable number.

204564561 is a deficient number, since it is larger than the sum of its proper divisors (74909487).

204564561 is an equidigital number, since it uses as much as digits as its factorization.

204564561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10072.

The product of its (nonzero) digits is 28800, while the sum is 33.

The square root of 204564561 is about 14302.6067903722. The cubic root of 204564561 is about 589.2190769492.

The spelling of 204564561 in words is "two hundred four million, five hundred sixty-four thousand, five hundred sixty-one".