21112212100 has 216 divisors, whose sum is σ = 55103250944. Its totient is φ = 6870528000.

The previous prime is 21112212067. The next prime is 21112212137. The reversal of 21112212100 is 121221112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 109389604 + ... + 109389796.

Almost surely, 2^21112212100 is an apocalyptic number.

21112212100 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 21112212100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27551625472).

21112212100 is an abundant number, since it is smaller than the sum of its proper divisors (33991038844).

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

21112212100 is a wasteful number, since it uses less digits than its factorization.

21112212100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387 (or 309 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21112212100 its reverse (121221112), we get a palindrome (21233433212).

The spelling of 21112212100 in words is "twenty-one billion, one hundred twelve million, two hundred twelve thousand, one hundred".