212221211221 has 2 divisors, whose sum is σ = 212221211222. Its totient is φ = 212221211220.

The previous prime is 212221211159. The next prime is 212221211231. The reversal of 212221211221 is 122112122212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 109253386225 + 102967824996 = 330535^2 + 320886^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-212221211221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212221211231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106110605610 + 106110605611.

It is an arithmetic number, because the mean of its divisors is an integer number (106110605611).

Almost surely, 2^212221211221 is an apocalyptic number.

It is an amenable number.

212221211221 is a deficient number, since it is larger than the sum of its proper divisors (1).

212221211221 is an equidigital number, since it uses as much as digits as its factorization.

212221211221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 128, while the sum is 19.

Adding to 212221211221 its reverse (122112122212), we get a palindrome (334333333433).

The spelling of 212221211221 in words is "two hundred twelve billion, two hundred twenty-one million, two hundred eleven thousand, two hundred twenty-one".