21864591108 has 72 divisors (see below), whose sum is σ = 57885225216. Its totient is φ = 6945523200.

The previous prime is 21864591079. The next prime is 21864591113. The reversal of 21864591108 is 80119546812.

It is a happy number.

21864591108 is a `hidden beast` number, since 2 + 1 + 86 + 459 + 110 + 8 = 666.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 175668 + ... + 273108.

Almost surely, 2^21864591108 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 21864591108, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28942612608).

21864591108 is an abundant number, since it is smaller than the sum of its proper divisors (36020634108).

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

21864591108 is a wasteful number, since it uses less digits than its factorization.

21864591108 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97745 (or 97740 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 45.

The spelling of 21864591108 in words is "twenty-one billion, eight hundred sixty-four million, five hundred ninety-one thousand, one hundred eight".