21100211221020 has 48 divisors (see below), whose sum is σ = 61117853196960. Its totient is φ = 5432698061056.

The previous prime is 21100211221009. The next prime is 21100211221057. The reversal of 21100211221020 is 2012211200112.

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

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, 6063277347 + ... + 6063280826.

It is an arithmetic number, because the mean of its divisors is an integer number (1273288608270).

Almost surely, 2^{21100211221020} is an apocalyptic number.

21100211221020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21100211221020 is an abundant number, since it is smaller than the sum of its proper divisors (40017641975940).

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

21100211221020 is a wasteful number, since it uses less digits than its factorization.

21100211221020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12126558214 (or 12126558212 counting only the distinct ones).

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

Adding to 21100211221020 its reverse (2012211200112), we get a palindrome (23112422421132).

The spelling of 21100211221020 in words is "twenty-one trillion, one hundred billion, two hundred eleven million, two hundred twenty-one thousand, twenty".