21563866422 has 72 divisors (see below), whose sum is σ = 56354600016. Its totient is φ = 5836823712.

The previous prime is 21563866391. The next prime is 21563866469. The reversal of 21563866422 is 22466836512.

21563866422 is a `hidden beast` number, since 2 + 1 + 5 + 638 + 6 + 6 + 4 + 2 + 2 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 191553 + ... + 282524.

It is an arithmetic number, because the mean of its divisors is an integer number (782702778).

Almost surely, 2^21563866422 is an apocalyptic number.

21563866422 is an abundant number, since it is smaller than the sum of its proper divisors (34790733594).

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

21563866422 is a wasteful number, since it uses less digits than its factorization.

21563866422 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 474130 (or 474108 counting only the distinct ones).

The product of its digits is 829440, while the sum is 45.

The spelling of 21563866422 in words is "twenty-one billion, five hundred sixty-three million, eight hundred sixty-six thousand, four hundred twenty-two".