21012312112 has 30 divisors (see below), whose sum is σ = 44748848564. Its totient is φ = 9551050080.

The previous prime is 21012312109. The next prime is 21012312157. The reversal of 21012312112 is 21121321012.

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

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5424798 + ... + 5428669.

Almost surely, 2^21012312112 is an apocalyptic number.

21012312112 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21012312112 is an abundant number, since it is smaller than the sum of its proper divisors (23736536452).

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

21012312112 is a wasteful number, since it uses less digits than its factorization.

21012312112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10853497 (or 10853480 counting only the distinct ones).

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

Adding to 21012312112 its reverse (21121321012), we get a palindrome (42133633124).

The spelling of 21012312112 in words is "twenty-one billion, twelve million, three hundred twelve thousand, one hundred twelve".