21312222012 has 60 divisors (see below), whose sum is σ = 55953673776. Its totient is φ = 7073559360.

The previous prime is 21312221951. The next prime is 21312222079. The reversal of 21312222012 is 21022221312.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 65664 + ... + 216647.

Almost surely, 2^21312222012 is an apocalyptic number.

It is an amenable number.

21312222012 is an abundant number, since it is smaller than the sum of its proper divisors (34641451764).

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

21312222012 is a wasteful number, since it uses less digits than its factorization.

21312222012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 282560 (or 282549 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21312222012 its reverse (21022221312), we get a palindrome (42334443324).

The spelling of 21312222012 in words is "twenty-one billion, three hundred twelve million, two hundred twenty-two thousand, twelve".