21102558372 has 168 divisors, whose sum is σ = 64174384512. Its totient is φ = 5943974400.

The previous prime is 21102558361. The next prime is 21102558391. The reversal of 21102558372 is 27385520112.

21102558372 is a `hidden beast` number, since 2 + 1 + 1 + 0 + 2 + 5 + 583 + 72 = 666.

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 55 ways as a sum of consecutive naturals, for example, 1441972 + ... + 1456532.

It is an arithmetic number, because the mean of its divisors is an integer number (381990384).

Almost surely, 2^21102558372 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 21102558372, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32087192256).

21102558372 is an abundant number, since it is smaller than the sum of its proper divisors (43071826140).

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

21102558372 is a wasteful number, since it uses less digits than its factorization.

21102558372 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14661 (or 14644 counting only the distinct ones).

The product of its (nonzero) digits is 33600, while the sum is 36.

The spelling of 21102558372 in words is "twenty-one billion, one hundred two million, five hundred fifty-eight thousand, three hundred seventy-two".