21121012120 has 32 divisors (see below), whose sum is σ = 51177838320. Its totient is φ = 7798527360.

The previous prime is 21121012103. The next prime is 21121012189. The reversal of 21121012120 is 2121012112.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a self number, because there is not a number n which added to its sum of digits gives 21121012120.

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, 20308146 + ... + 20309185.

Almost surely, 2^21121012120 is an apocalyptic number.

21121012120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21121012120 is an abundant number, since it is smaller than the sum of its proper divisors (30056826200).

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

21121012120 is a wasteful number, since it uses less digits than its factorization.

21121012120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40617355 (or 40617351 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21121012120 its reverse (2121012112), we get a palindrome (23242024232).

The spelling of 21121012120 in words is "twenty-one billion, one hundred twenty-one million, twelve thousand, one hundred twenty".