561163221 has 40 divisors (see below), whose sum is σ = 861256704. Its totient is φ = 363955680.

The previous prime is 561163193. The next prime is 561163241. The reversal of 561163221 is 122361165.

561163221 is a `hidden beast` number, since 5 + 6 + 1 + 1 + 632 + 21 = 666.

It is not a de Polignac number, because 561163221 - 2⁵ = 561163189 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561163241) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 848631 + ... + 849291.

Almost surely, 2^561163221 is an apocalyptic number.

It is an amenable number.

561163221 is a deficient number, since it is larger than the sum of its proper divisors (300093483).

561163221 is a wasteful number, since it uses less digits than its factorization.

561163221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 943 (or 934 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 561163221 is about 23688.8839120799. The cubic root of 561163221 is about 824.8273754525.

The spelling of 561163221 in words is "five hundred sixty-one million, one hundred sixty-three thousand, two hundred twenty-one".