22221218021 has 2 divisors, whose sum is σ = 22221218022. Its totient is φ = 22221218020.

The previous prime is 22221217961. The next prime is 22221218027. The reversal of 22221218021 is 12081212222.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16234327396 + 5986890625 = 127414^2 + 77375^2 .

It is a cyclic number.

It is not a de Polignac number, because 22221218021 - 2⁶ = 22221217957 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22221218027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11110609010 + 11110609011.

It is an arithmetic number, because the mean of its divisors is an integer number (11110609011).

Almost surely, 2^22221218021 is an apocalyptic number.

It is an amenable number.

22221218021 is a deficient number, since it is larger than the sum of its proper divisors (1).

22221218021 is an equidigital number, since it uses as much as digits as its factorization.

22221218021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 512, while the sum is 23.

The spelling of 22221218021 in words is "twenty-two billion, two hundred twenty-one million, two hundred eighteen thousand, twenty-one".