22222121221 has 2 divisors, whose sum is σ = 22222121222. Its totient is φ = 22222121220.

The previous prime is 22222121179. The next prime is 22222121261. The reversal of 22222121221 is 12212122222.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20018288196 + 2203833025 = 141486^2 + 46945^2 .

It is a cyclic number.

It is not a de Polignac number, because 22222121221 - 2⁷ = 22222121093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22222121261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11111060610 + 11111060611.

It is an arithmetic number, because the mean of its divisors is an integer number (11111060611).

Almost surely, 2^22222121221 is an apocalyptic number.

It is an amenable number.

22222121221 is a deficient number, since it is larger than the sum of its proper divisors (1).

22222121221 is an equidigital number, since it uses as much as digits as its factorization.

22222121221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 256, while the sum is 19.

Adding to 22222121221 its reverse (12212122222), we get a palindrome (34434243443).

The spelling of 22222121221 in words is "twenty-two billion, two hundred twenty-two million, one hundred twenty-one thousand, two hundred twenty-one".