21312012112 has 20 divisors (see below), whose sum is σ = 43465288480. Its totient is φ = 10095163488.

The previous prime is 21312012077. The next prime is 21312012119. The reversal of 21312012112 is 21121021312.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21312012119) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35052348 + ... + 35052955.

It is an arithmetic number, because the mean of its divisors is an integer number (2173264424).

Almost surely, 2^21312012112 is an apocalyptic number.

It is an amenable number.

21312012112 is an abundant number, since it is smaller than the sum of its proper divisors (22153276368).

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

21312012112 is a wasteful number, since it uses less digits than its factorization.

21312012112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70105330 (or 70105324 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 21312012112 its reverse (21121021312), we get a palindrome (42433033424).

The spelling of 21312012112 in words is "twenty-one billion, three hundred twelve million, twelve thousand, one hundred twelve".