21120111012 has 240 divisors, whose sum is σ = 66767980160. Its totient is φ = 5059929600.

The previous prime is 21120110987. The next prime is 21120111017. The reversal of 21120111012 is 21011102112.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is not an unprimeable number, because it can be changed into a prime (21120111017) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 15987312 + ... + 15988632.

Almost surely, 2^21120111012 is an apocalyptic number.

21120111012 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21120111012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33383990080).

21120111012 is an abundant number, since it is smaller than the sum of its proper divisors (45647869148).

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

21120111012 is a wasteful number, since it uses less digits than its factorization.

21120111012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1392 (or 1357 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21120111012 its reverse (21011102112), we get a palindrome (42131213124).

The spelling of 21120111012 in words is "twenty-one billion, one hundred twenty million, one hundred eleven thousand, twelve".