21100010200020 has 96 divisors (see below), whose sum is σ = 65698153194240. Its totient is φ = 5622068499840.

The previous prime is 21100010200007. The next prime is 21100010200051. The reversal of 21100010200020 is 2000201000112.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21100010199975 and 21100010200011.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 15314271 + ... + 16635110.

It is an arithmetic number, because the mean of its divisors is an integer number (684355762440).

Almost surely, 2^{21100010200020} is an apocalyptic number.

21100010200020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21100010200020 is an abundant number, since it is smaller than the sum of its proper divisors (44598142994220).

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

21100010200020 is a wasteful number, since it uses less digits than its factorization.

21100010200020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31950622 (or 31950614 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21100010200020 its reverse (2000201000112), we get a palindrome (23100211200132).

The spelling of 21100010200020 in words is "twenty-one trillion, one hundred billion, ten million, two hundred thousand, twenty".