205021564 has 24 divisors (see below), whose sum is σ = 414430128. Its totient is φ = 87709440.

The previous prime is 205021559. The next prime is 205021577. The reversal of 205021564 is 465120502.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 136299 + ... + 137794.

It is an arithmetic number, because the mean of its divisors is an integer number (17267922).

Almost surely, 2^205021564 is an apocalyptic number.

It is an amenable number.

205021564 is an abundant number, since it is smaller than the sum of its proper divisors (209408564).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

205021564 is a wasteful number, since it uses less digits than its factorization.

205021564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 274125 (or 274123 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 205021564 is about 14318.5740910190. The cubic root of 205021564 is about 589.6575279536.

The spelling of 205021564 in words is "two hundred five million, twenty-one thousand, five hundred sixty-four".