21577638725 has 48 divisors (see below), whose sum is σ = 27865109376. Its totient is φ = 16561440000.

The previous prime is 21577638713. The next prime is 21577638749. The reversal of 21577638725 is 52783677512.

It is not a de Polignac number, because 21577638725 - 2⁶ = 21577638661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 30780875 + ... + 30781575.

It is an arithmetic number, because the mean of its divisors is an integer number (580523112).

Almost surely, 2^21577638725 is an apocalyptic number.

21577638725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21577638725 is a deficient number, since it is larger than the sum of its proper divisors (6287470651).

21577638725 is a wasteful number, since it uses less digits than its factorization.

21577638725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1166 (or 1161 counting only the distinct ones).

The product of its digits is 4939200, while the sum is 53.

The spelling of 21577638725 in words is "twenty-one billion, five hundred seventy-seven million, six hundred thirty-eight thousand, seven hundred twenty-five".