21112112112 has 160 divisors (see below), whose sum is σ = 67572341760. Its totient is φ = 5530982400.

The previous prime is 21112112107. The next prime is 21112112123. The reversal of 21112112112 is 21121121112.

It is a happy number.

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 21112112091 and 21112112100.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 643564 + ... + 675572.

It is an arithmetic number, because the mean of its divisors is an integer number (422327136).

Almost surely, 2^21112112112 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21112112112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33786170880).

21112112112 is an abundant number, since it is smaller than the sum of its proper divisors (46460229648).

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

21112112112 is a wasteful number, since it uses less digits than its factorization.

21112112112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32191 (or 32185 counting only the distinct ones).

The product of its digits is 16, while the sum is 15.

Adding to 21112112112 its reverse (21121121112), we get a palindrome (42233233224).

The spelling of 21112112112 in words is "twenty-one billion, one hundred twelve million, one hundred twelve thousand, one hundred twelve".