21312122112 has 144 divisors (see below), whose sum is σ = 63110544000. Its totient is φ = 7094255616.

The previous prime is 21312122099. The next prime is 21312122119. The reversal of 21312122112 is 21122121312.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (18).

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 congruent number.

It is not an unprimeable number, because it can be changed into a prime (21312122119) 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, 6419589 + ... + 6422907.

Almost surely, 2^21312122112 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 21312122112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31555272000).

21312122112 is an abundant number, since it is smaller than the sum of its proper divisors (41798421888).

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

21312122112 is an equidigital number, since it uses as much as digits as its factorization.

21312122112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4273 (or 4253 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

Adding to 21312122112 its reverse (21122121312), we get a palindrome (42434243424).

The spelling of 21312122112 in words is "twenty-one billion, three hundred twelve million, one hundred twenty-two thousand, one hundred twelve".