21531112044 has 48 divisors (see below), whose sum is σ = 54295110912. Its totient is φ = 6601534272.

The previous prime is 21531112033. The next prime is 21531112067. The reversal of 21531112044 is 44021113512.

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, 199704 + ... + 287999.

It is an arithmetic number, because the mean of its divisors is an integer number (1131148144).

Almost surely, 2^21531112044 is an apocalyptic number.

It is an amenable number.

21531112044 is an abundant number, since it is smaller than the sum of its proper divisors (32763998868).

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

21531112044 is a wasteful number, since it uses less digits than its factorization.

21531112044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 488006 (or 488004 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

Adding to 21531112044 its reverse (44021113512), we get a palindrome (65552225556).

The spelling of 21531112044 in words is "twenty-one billion, five hundred thirty-one million, one hundred twelve thousand, forty-four".