21985818624 has 432 divisors, whose sum is σ = 80617806360. Its totient is φ = 5708021760.

The previous prime is 21985818619. The next prime is 21985818637. The reversal of 21985818624 is 42681858912.

21985818624 is a `hidden beast` number, since 2 + 1 + 9 + 8 + 5 + 8 + 1 + 8 + 624 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 9933742 + ... + 9935954.

Almost surely, 2^21985818624 is an apocalyptic number.

21985818624 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21985818624, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40308903180).

21985818624 is an abundant number, since it is smaller than the sum of its proper divisors (58631987736).

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

21985818624 is a wasteful number, since it uses less digits than its factorization.

21985818624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2266 (or 2236 counting only the distinct ones).

The product of its digits is 2211840, while the sum is 54.

The spelling of 21985818624 in words is "twenty-one billion, nine hundred eighty-five million, eight hundred eighteen thousand, six hundred twenty-four".