561564 has 36 divisors (see below), whose sum is σ = 1496040. Its totient is φ = 177120.

The previous prime is 561559. The next prime is 561599. The reversal of 561564 is 465165.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 274 + ... + 1094.

2⁵⁶¹⁵⁶⁴ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 561564, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (748020).

561564 is an abundant number, since it is smaller than the sum of its proper divisors (934476).

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

561564 is a wasteful number, since it uses less digits than its factorization.

561564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 850 (or 845 counting only the distinct ones).

The product of its digits is 3600, while the sum is 27.

The square root of 561564 is about 749.3757401998. The cubic root of 561564 is about 82.5023690780.

The spelling of 561564 in words is "five hundred sixty-one thousand, five hundred sixty-four".