21912111820800 has 1872 divisors, whose sum is σ = 87665392389120. Its totient is φ = 5207556096000.

The previous prime is 21912111820793. The next prime is 21912111820811. The reversal of 21912111820800 is 802811121912.

It is a happy number.

21912111820800 is a `hidden beast` number, since 2 + 191 + 211 + 182 + 0 + 80 + 0 = 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 143 ways as a sum of consecutive naturals, for example, 20084428255 + ... + 20084429345.

Almost surely, 2^{21912111820800} is an apocalyptic number.

21912111820800 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 21912111820800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43832696194560).

21912111820800 is an abundant number, since it is smaller than the sum of its proper divisors (65753280568320).

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

21912111820800 is a wasteful number, since it uses less digits than its factorization.

21912111820800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1218 (or 1188 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 36.

The spelling of 21912111820800 in words is "twenty-one trillion, nine hundred twelve billion, one hundred eleven million, eight hundred twenty thousand, eight hundred".