21111312120 has 64 divisors (see below), whose sum is σ = 65517876000. Its totient is φ = 5435555328.

The previous prime is 21111312073. The next prime is 21111312127. The reversal of 21111312120 is 2121311112.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21111312120.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111312127) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3029755 + ... + 3036714.

Almost surely, 2^21111312120 is an apocalyptic number.

21111312120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21111312120 is an abundant number, since it is smaller than the sum of its proper divisors (44406563880).

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

21111312120 is a wasteful number, since it uses less digits than its factorization.

21111312120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6066512 (or 6066508 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 15.

Adding to 21111312120 its reverse (2121311112), we get a palindrome (23232623232).

The spelling of 21111312120 in words is "twenty-one billion, one hundred eleven million, three hundred twelve thousand, one hundred twenty".