21222112012121 has 4 divisors (see below), whose sum is σ = 21230470467600. Its totient is φ = 21213753556644.

The previous prime is 21222112012097. The next prime is 21222112012163. The reversal of 21222112012121 is 12121021122212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21222112012121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21222112012093 and 21222112012102.

It is not an unprimeable number, because it can be changed into a prime (21222112012421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4179223931 + ... + 4179229008.

It is an arithmetic number, because the mean of its divisors is an integer number (5307617616900).

Almost surely, 2^{21222112012121} is an apocalyptic number.

It is an amenable number.

21222112012121 is a deficient number, since it is larger than the sum of its proper divisors (8358455479).

21222112012121 is an equidigital number, since it uses as much as digits as its factorization.

21222112012121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8358455478.

The product of its (nonzero) digits is 128, while the sum is 20.

Adding to 21222112012121 its reverse (12121021122212), we get a palindrome (33343133134333).

The spelling of 21222112012121 in words is "twenty-one trillion, two hundred twenty-two billion, one hundred twelve million, twelve thousand, one hundred twenty-one".