21642561325 has 72 divisors (see below), whose sum is σ = 35849178720. Its totient is φ = 12781238400.

The previous prime is 21642561299. The next prime is 21642561337. The reversal of 21642561325 is 52316524612.

It is not a de Polignac number, because 21642561325 - 2¹¹ = 21642559277 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 213759 + ... + 298291.

It is an arithmetic number, because the mean of its divisors is an integer number (497905260).

Almost surely, 2^21642561325 is an apocalyptic number.

21642561325 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21642561325 is a deficient number, since it is larger than the sum of its proper divisors (14206617395).

21642561325 is a wasteful number, since it uses less digits than its factorization.

21642561325 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84587 (or 84575 counting only the distinct ones).

The product of its digits is 86400, while the sum is 37.

The spelling of 21642561325 in words is "twenty-one billion, six hundred forty-two million, five hundred sixty-one thousand, three hundred twenty-five".