21088844672 has 128 divisors (see below), whose sum is σ = 50009702400. Its totient is φ = 8667832320.

The previous prime is 21088844663. The next prime is 21088844683. The reversal of 21088844672 is 27644888012.

It is a tau number, because it is divible by the number of its divisors (128).

It is a self number, because there is not a number n which added to its sum of digits gives 21088844672.

It is a congruent number.

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, 3135329 + ... + 3142047.

It is an arithmetic number, because the mean of its divisors is an integer number (390700800).

Almost surely, 2^21088844672 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 21088844672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25004851200).

21088844672 is an abundant number, since it is smaller than the sum of its proper divisors (28920857728).

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

21088844672 is a wasteful number, since it uses less digits than its factorization.

21088844672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6884 (or 6872 counting only the distinct ones).

The product of its (nonzero) digits is 1376256, while the sum is 50.

The spelling of 21088844672 in words is "twenty-one billion, eighty-eight million, eight hundred forty-four thousand, six hundred seventy-two".