21312000012 has 12 divisors (see below), whose sum is σ = 49728000056. Its totient is φ = 7104000000.

The previous prime is 21311999987. The next prime is 21312000029. The reversal of 21312000012 is 21000021312.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×21312000012² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12), and also a Moran number because the ratio is a prime number: 1776000001 = 21312000012 / (2 + 1 + 3 + 1 + 2 + 0 + 0 + 0 + 0 + 1 + 2).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 887999989 + ... + 888000012.

Almost surely, 2^21312000012 is an apocalyptic number.

It is an amenable number.

21312000012 is an abundant number, since it is smaller than the sum of its proper divisors (28416000044).

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

21312000012 is a wasteful number, since it uses less digits than its factorization.

21312000012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1776000008 (or 1776000006 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 21312000012 its reverse (21000021312), we get a palindrome (42312021324).

The spelling of 21312000012 in words is "twenty-one billion, three hundred twelve million, twelve", and thus it is an aban number.