21100312120 has 32 divisors (see below), whose sum is σ = 47507011920. Its totient is φ = 8434558720.

The previous prime is 21100312111. The next prime is 21100312133. The reversal of 21100312120 is 2121300112.

It is a super-2 number, since 2×21100312120² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21100312120.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 112261 + ... + 234100.

Almost surely, 2^21100312120 is an apocalyptic number.

21100312120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21100312120 is an abundant number, since it is smaller than the sum of its proper divisors (26406699800).

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

21100312120 is a wasteful number, since it uses less digits than its factorization.

21100312120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 347895 (or 347891 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21100312120 its reverse (2121300112), we get a palindrome (23221612232).

The spelling of 21100312120 in words is "twenty-one billion, one hundred million, three hundred twelve thousand, one hundred twenty".