561566660 has 24 divisors (see below), whose sum is σ = 1241358720. Its totient is φ = 212804064.

The previous prime is 561566651. The next prime is 561566683. The reversal of 561566660 is 66665165.

It is a super-2 number, since 2×561566660² = 630714227247111200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 738524 + ... + 739283.

It is an arithmetic number, because the mean of its divisors is an integer number (51723280).

Almost surely, 2^561566660 is an apocalyptic number.

It is an amenable number.

561566660 is an abundant number, since it is smaller than the sum of its proper divisors (679792060).

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

561566660 is a wasteful number, since it uses less digits than its factorization.

561566660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1477835 (or 1477833 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 41.

The square root of 561566660 is about 23697.3977474321. The cubic root of 561566660 is about 825.0249934271.

The spelling of 561566660 in words is "five hundred sixty-one million, five hundred sixty-six thousand, six hundred sixty".