21221101012100 has 108 divisors (see below), whose sum is σ = 50746841772900. Its totient is φ = 7696924857600.

The previous prime is 21221101012063. The next prime is 21221101012123. The reversal of 21221101012100 is 121010112212.

It can be written as a sum of positive squares in 6 ways, for example, as 123780126976 + 21097320885124 = 351824^2 + 4593182^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 2452646 + ... + 6961154.

Almost surely, 2^{21221101012100} is an apocalyptic number.

21221101012100 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 21221101012100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25373420886450).

21221101012100 is an abundant number, since it is smaller than the sum of its proper divisors (29525740760800).

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

21221101012100 is a wasteful number, since it uses less digits than its factorization.

21221101012100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4508934 (or 4508916 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21221101012100 its reverse (121010112212), we get a palindrome (21342111124312).

The spelling of 21221101012100 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred one million, twelve thousand, one hundred".