21564922500 has 405 divisors, whose sum is σ = 75723520873. Its totient is φ = 5169120000.

The previous prime is 21564922471. The next prime is 21564922517. The reversal of 21564922500 is 522946512.

The square root of 21564922500 is 146850.

It is a perfect power (a square), and thus also a powerful number.

21564922500 is a `hidden beast` number, since 2 + 1 + 5 + 64 + 92 + 2 + 500 = 666.

It can be written as a sum of positive squares in 7 ways, for example, as 20949088644 + 615833856 = 144738^2 + 24816^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 242302456 + ... + 242302544.

Almost surely, 2^21564922500 is an apocalyptic number.

21564922500 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

21564922500 is the 146850-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21564922500

21564922500 is an abundant number, since it is smaller than the sum of its proper divisors (54158598373).

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

21564922500 is a wasteful number, since it uses less digits than its factorization.

21564922500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230 (or 110 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

Multiplying 21564922500 by its sum of digits (36), we get a square (776337210000 = 881100²).

21564922500 divided by its sum of digits (36) gives a square (599025625 = 24475²).

The spelling of 21564922500 in words is "twenty-one billion, five hundred sixty-four million, nine hundred twenty-two thousand, five hundred".