22121211111221 has 2 divisors, whose sum is σ = 22121211111222. Its totient is φ = 22121211111220.

The previous prime is 22121211111217. The next prime is 22121211111227. The reversal of 22121211111221 is 12211111212122.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21327641930596 + 793569180625 = 4618186^2 + 890825^2 .

It is a cyclic number.

It is not a de Polignac number, because 22121211111221 - 2² = 22121211111217 is a prime.

It is a super-2 number, since 2×22121211111221² (a number of 27 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 22121211111193 and 22121211111202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22121211111227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11060605555610 + 11060605555611.

It is an arithmetic number, because the mean of its divisors is an integer number (11060605555611).

Almost surely, 2^{22121211111221} is an apocalyptic number.

It is an amenable number.

22121211111221 is a deficient number, since it is larger than the sum of its proper divisors (1).

22121211111221 is an equidigital number, since it uses as much as digits as its factorization.

22121211111221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 64, while the sum is 20.

Adding to 22121211111221 its reverse (12211111212122), we get a palindrome (34332322323343).

The spelling of 22121211111221 in words is "twenty-two trillion, one hundred twenty-one billion, two hundred eleven million, one hundred eleven thousand, two hundred twenty-one".