21031220012100 has 36 divisors (see below), whose sum is σ = 60850329902544. Its totient is φ = 5608325336480.

The previous prime is 21031220012053. The next prime is 21031220012107. The reversal of 21031220012100 is 121002213012.

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 21031220012100.

It is not an unprimeable number, because it can be changed into a prime (21031220012107) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35052033054 + ... + 35052033653.

Almost surely, 2^{21031220012100} is an apocalyptic number.

21031220012100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21031220012100 is an abundant number, since it is smaller than the sum of its proper divisors (39819109890444).

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

21031220012100 is a wasteful number, since it uses less digits than its factorization.

21031220012100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70104066724 (or 70104066717 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 21031220012100 its reverse (121002213012), we get a palindrome (21152222225112).

The spelling of 21031220012100 in words is "twenty-one trillion, thirty-one billion, two hundred twenty million, twelve thousand, one hundred".