21252445566 has 24 divisors (see below), whose sum is σ = 46720253832. Its totient is φ = 6440134800.

The previous prime is 21252445561. The next prime is 21252445589. The reversal of 21252445566 is 66554425212.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21252445561) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 14635945 + ... + 14637396.

It is an arithmetic number, because the mean of its divisors is an integer number (1946677243).

Almost surely, 2^21252445566 is an apocalyptic number.

21252445566 is an abundant number, since it is smaller than the sum of its proper divisors (25467808266).

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

21252445566 is a wasteful number, since it uses less digits than its factorization.

21252445566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29273368 (or 29273357 counting only the distinct ones).

The product of its digits is 576000, while the sum is 42.

The spelling of 21252445566 in words is "twenty-one billion, two hundred fifty-two million, four hundred forty-five thousand, five hundred sixty-six".