21912508800 has 960 divisors, whose sum is σ = 99629560800. Its totient is φ = 4618321920.

The previous prime is 21912508789. The next prime is 21912508831. The reversal of 21912508800 is 880521912.

It is a tau number, because it is divible by the number of its divisors (960).

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 23586736 + ... + 23587664.

Almost surely, 2^21912508800 is an apocalyptic number.

21912508800 is a gapful number since it is divisible by the number (20) 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 21912508800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49814780400).

21912508800 is an abundant number, since it is smaller than the sum of its proper divisors (77717052000).

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

21912508800 is a wasteful number, since it uses less digits than its factorization.

21912508800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 985 (or 959 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 36.

The spelling of 21912508800 in words is "twenty-one billion, nine hundred twelve million, five hundred eight thousand, eight hundred".