21644761088 has 96 divisors (see below), whose sum is σ = 47130174000. Its totient is φ = 9898721280.

The previous prime is 21644761067. The next prime is 21644761111. The reversal of 21644761088 is 88016744612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1118858 + ... + 1138038.

Almost surely, 2^21644761088 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21644761088, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23565087000).

21644761088 is an abundant number, since it is smaller than the sum of its proper divisors (25485412912).

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

21644761088 is a wasteful number, since it uses less digits than its factorization.

21644761088 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19251 (or 19231 counting only the distinct ones).

The product of its (nonzero) digits is 516096, while the sum is 47.

The spelling of 21644761088 in words is "twenty-one billion, six hundred forty-four million, seven hundred sixty-one thousand, eighty-eight".