21102120100020 has 48 divisors (see below), whose sum is σ = 59123836437120. Its totient is φ = 5623622487936.

The previous prime is 21102120099989. The next prime is 21102120100043. The reversal of 21102120100020 is 2000102120112.

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

It is a junction number, because it is equal to n+sod(n) for n = 21102120099969 and 21102120100005.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 112703767 + ... + 112890846.

It is an arithmetic number, because the mean of its divisors is an integer number (1231746592440).

Almost surely, 2^{21102120100020} is an apocalyptic number.

21102120100020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21102120100020 is an abundant number, since it is smaller than the sum of its proper divisors (38021716337100).

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

21102120100020 is a wasteful number, since it uses less digits than its factorization.

21102120100020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 225596184 (or 225596182 counting only the distinct ones).

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

Adding to 21102120100020 its reverse (2000102120112), we get a palindrome (23102222220132).

The spelling of 21102120100020 in words is "twenty-one trillion, one hundred two billion, one hundred twenty million, one hundred thousand, twenty".