21222120012100 has 144 divisors (see below), whose sum is σ = 53875609879168. Its totient is φ = 7104200463360.

The previous prime is 21222120012073. The next prime is 21222120012101. The reversal of 21222120012100 is 121002122212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21222120012101) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 78636994 + ... + 78906406.

Almost surely, 2^{21222120012100} is an apocalyptic number.

21222120012100 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 21222120012100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26937804939584).

21222120012100 is an abundant number, since it is smaller than the sum of its proper divisors (32653489867068).

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

21222120012100 is a wasteful number, since it uses less digits than its factorization.

21222120012100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 272094 (or 272087 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21222120012100 its reverse (121002122212), we get a palindrome (21343122134312).

The spelling of 21222120012100 in words is "twenty-one trillion, two hundred twenty-two billion, one hundred twenty million, twelve thousand, one hundred".