21121221220212 has 24 divisors (see below), whose sum is σ = 49282927578976. Its totient is φ = 7040395921248.

The previous prime is 21121221220193. The next prime is 21121221220241. The reversal of 21121221220212 is 21202212212112.

It is a super-2 number, since 2×21121221220212² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10681143 + ... + 12503169.

Almost surely, 2^{21121221220212} is an apocalyptic number.

It is an amenable number.

21121221220212 is an abundant number, since it is smaller than the sum of its proper divisors (28161706358764).

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

21121221220212 is a wasteful number, since it uses less digits than its factorization.

21121221220212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2788047 (or 2788045 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 21.

Adding to 21121221220212 its reverse (21202212212112), we get a palindrome (42323433432324).

The spelling of 21121221220212 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred twenty-one million, two hundred twenty thousand, two hundred twelve".