21225108672 has 112 divisors (see below), whose sum is σ = 62619818880. Its totient is φ = 7049873664.

The previous prime is 21225108659. The next prime is 21225108727. The reversal of 21225108672 is 27680152212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 467323 + ... + 510725.

Almost surely, 2^21225108672 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 21225108672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31309909440).

21225108672 is an abundant number, since it is smaller than the sum of its proper divisors (41394710208).

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

21225108672 is a wasteful number, since it uses less digits than its factorization.

21225108672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43707 (or 43691 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The spelling of 21225108672 in words is "twenty-one billion, two hundred twenty-five million, one hundred eight thousand, six hundred seventy-two".