21312120012 has 12 divisors (see below), whose sum is σ = 49728280056. Its totient is φ = 7104040000.

The previous prime is 21312119993. The next prime is 21312120029. The reversal of 21312120012 is 21002121312.

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

It is a junction number, because it is equal to n+sod(n) for n = 21312119973 and 21312120000.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 888004989 + ... + 888005012.

It is an arithmetic number, because the mean of its divisors is an integer number (4144023338).

Almost surely, 2^21312120012 is an apocalyptic number.

It is an amenable number.

21312120012 is an abundant number, since it is smaller than the sum of its proper divisors (28416160044).

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

21312120012 is a wasteful number, since it uses less digits than its factorization.

21312120012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1776010008 (or 1776010006 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 21312120012 its reverse (21002121312), we get a palindrome (42314241324).

The spelling of 21312120012 in words is "twenty-one billion, three hundred twelve million, one hundred twenty thousand, twelve".