21221121200100 has 72 divisors (see below), whose sum is σ = 61400653835808. Its totient is φ = 5658884870400.

The previous prime is 21221121200023. The next prime is 21221121200101. The reversal of 21221121200100 is 100212112212.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21221121200100.

It is not an unprimeable number, because it can be changed into a prime (21221121200101) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 22252272 + ... + 23186328.

Almost surely, 2^{21221121200100} is an apocalyptic number.

21221121200100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221121200100 is an abundant number, since it is smaller than the sum of its proper divisors (40179532635708).

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

21221121200100 is a wasteful number, since it uses less digits than its factorization.

21221121200100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1009805 (or 1009798 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21221121200100 its reverse (100212112212), we get a palindrome (21321333312312).

The spelling of 21221121200100 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred twenty-one million, two hundred thousand, one hundred".