21222222121200 has 480 divisors, whose sum is σ = 70611155596800. Its totient is φ = 5442011688960.

The previous prime is 21222222121181. The next prime is 21222222121211. The reversal of 21222222121200 is 212122222212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 16287199749 + ... + 16287201051.

It is an arithmetic number, because the mean of its divisors is an integer number (147106574160).

Almost surely, 2^{21222222121200} is an apocalyptic number.

21222222121200 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 21222222121200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35305577798400).

21222222121200 is an abundant number, since it is smaller than the sum of its proper divisors (49388933475600).

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

21222222121200 is a wasteful number, since it uses less digits than its factorization.

21222222121200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2889 (or 2878 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 21.

Adding to 21222222121200 its reverse (212122222212), we get a palindrome (21434344343412).

The spelling of 21222222121200 in words is "twenty-one trillion, two hundred twenty-two billion, two hundred twenty-two million, one hundred twenty-one thousand, two hundred".