21121112012 has 96 divisors (see below), whose sum is σ = 49684776960. Its totient is φ = 7587198720.

The previous prime is 21121112011. The next prime is 21121112017. The reversal of 21121112012 is 21021112112.

It is a super-2 number, since 2×21121112012² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is not an unprimeable number, because it can be changed into a prime (21121112011) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4157618 + ... + 4162694.

It is an arithmetic number, because the mean of its divisors is an integer number (517549760).

Almost surely, 2^21121112012 is an apocalyptic number.

21121112012 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 21121112012, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24842388480).

21121112012 is an abundant number, since it is smaller than the sum of its proper divisors (28563664948).

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

21121112012 is a wasteful number, since it uses less digits than its factorization.

21121112012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6151 (or 6149 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21121112012 its reverse (21021112112), we get a palindrome (42142224124).

The spelling of 21121112012 in words is "twenty-one billion, one hundred twenty-one million, one hundred twelve thousand, twelve".