21564563250 has 32 divisors (see below), whose sum is σ = 53825151744. Its totient is φ = 5750550000.

The previous prime is 21564563249. The next prime is 21564563269. The reversal of 21564563250 is 5236546512.

It is a junction number, because it is equal to n+sod(n) for n = 21564563199 and 21564563208.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14375626 + ... + 14377125.

It is an arithmetic number, because the mean of its divisors is an integer number (1682035992).

Almost surely, 2^21564563250 is an apocalyptic number.

21564563250 is an abundant number, since it is smaller than the sum of its proper divisors (32260588494).

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

21564563250 is a wasteful number, since it uses less digits than its factorization.

21564563250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28752771 (or 28752761 counting only the distinct ones).

The product of its (nonzero) digits is 216000, while the sum is 39.

The spelling of 21564563250 in words is "twenty-one billion, five hundred sixty-four million, five hundred sixty-three thousand, two hundred fifty".