21612124056 has 16 divisors (see below), whose sum is σ = 54030310200. Its totient is φ = 7204041344.

The previous prime is 21612123997. The next prime is 21612124081. The reversal of 21612124056 is 65042121612.

It is a super-2 number, since 2×21612124056² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 450252561 + ... + 450252608.

Almost surely, 2^21612124056 is an apocalyptic number.

It is an amenable number.

21612124056 is an abundant number, since it is smaller than the sum of its proper divisors (32418186144).

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

21612124056 is a wasteful number, since it uses less digits than its factorization.

21612124056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 900505178 (or 900505174 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 30.

Adding to 21612124056 its reverse (65042121612), we get a palindrome (86654245668).

The spelling of 21612124056 in words is "twenty-one billion, six hundred twelve million, one hundred twenty-four thousand, fifty-six".