21101100120 has 96 divisors (see below), whose sum is σ = 68596491600. Its totient is φ = 5625490176.

The previous prime is 21101100109. The next prime is 21101100127. The reversal of 21101100120 is 2100110112.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101100127) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2747646 + ... + 2755314.

Almost surely, 2^21101100120 is an apocalyptic number.

21101100120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21101100120 is an abundant number, since it is smaller than the sum of its proper divisors (47495391480).

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

21101100120 is a wasteful number, since it uses less digits than its factorization.

21101100120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15329 (or 15322 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21101100120 its reverse (2100110112), we get a palindrome (23201210232).

The spelling of 21101100120 in words is "twenty-one billion, one hundred one million, one hundred thousand, one hundred twenty".