21221200100100 has 576 divisors, whose sum is σ = 82466201825280. Its totient is φ = 4069065369600.

The previous prime is 21221200100081. The next prime is 21221200100129. The reversal of 21221200100100 is 100100212212.

It is a super-3 number, since 3×21221200100100³ (a number of 41 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 1084974121 + ... + 1084993679.

It is an arithmetic number, because the mean of its divisors is an integer number (143170489280).

Almost surely, 2^{21221200100100} is an apocalyptic number.

21221200100100 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 21221200100100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41233100912640).

21221200100100 is an abundant number, since it is smaller than the sum of its proper divisors (61245001725180).

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

21221200100100 is a wasteful number, since it uses less digits than its factorization.

21221200100100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23220 (or 23213 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21221200100100 its reverse (100100212212), we get a palindrome (21321300312312).

The spelling of 21221200100100 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred million, one hundred thousand, one hundred".