564021561 has 4 divisors (see below), whose sum is σ = 752028752. Its totient is φ = 376014372.

The previous prime is 564021559. The next prime is 564021589. The reversal of 564021561 is 165120465.

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 not a de Polignac number, because 564021561 - 2¹ = 564021559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (564021361) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 94003591 + ... + 94003596.

It is an arithmetic number, because the mean of its divisors is an integer number (188007188).

Almost surely, 2^564021561 is an apocalyptic number.

It is an amenable number.

564021561 is a deficient number, since it is larger than the sum of its proper divisors (188007191).

564021561 is a wasteful number, since it uses less digits than its factorization.

564021561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188007190.

The product of its (nonzero) digits is 7200, while the sum is 30.

The square root of 564021561 is about 23749.1381106768. The cubic root of 564021561 is about 826.2254508130.

The spelling of 564021561 in words is "five hundred sixty-four million, twenty-one thousand, five hundred sixty-one".