21121221112200 has 1152 divisors, whose sum is σ = 83866082227200. Its totient is φ = 4890036096000.

The previous prime is 21121221112181. The next prime is 21121221112231. The reversal of 21121221112200 is 221112212112.

21121221112200 is a `hidden beast` number, since 21 + 1 + 212 + 211 + 1 + 220 + 0 = 666.

It is a super-2 number, since 2×21121221112200² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 13045842991 + ... + 13045844609.

It is an arithmetic number, because the mean of its divisors is an integer number (72800418600).

Almost surely, 2^{21121221112200} is an apocalyptic number.

21121221112200 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 21121221112200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41933041113600).

21121221112200 is an abundant number, since it is smaller than the sum of its proper divisors (62744861115000).

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

21121221112200 is a wasteful number, since it uses less digits than its factorization.

21121221112200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2745 (or 2724 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21121221112200 its reverse (221112212112), we get a palindrome (21342333324312).

The spelling of 21121221112200 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred twenty-one million, one hundred twelve thousand, two hundred".