21312221212 has 12 divisors (see below), whose sum is σ = 37417875880. Its totient is φ = 10621399536.

The previous prime is 21312221201. The next prime is 21312221213. The reversal of 21312221212 is 21212221312.

It is a self number, because there is not a number n which added to its sum of digits gives 21312221212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21312221213) by changing a digit.

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, 8676387 + ... + 8678842.

Almost surely, 2^21312221212 is an apocalyptic number.

It is an amenable number.

21312221212 is a deficient number, since it is larger than the sum of its proper divisors (16105654668).

21312221212 is a wasteful number, since it uses less digits than its factorization.

21312221212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17355540 (or 17355538 counting only the distinct ones).

The product of its digits is 192, while the sum is 19.

Adding to 21312221212 its reverse (21212221312), we get a palindrome (42524442524).

The spelling of 21312221212 in words is "twenty-one billion, three hundred twelve million, two hundred twenty-one thousand, two hundred twelve".