221212211022221 has 2 divisors, whose sum is σ = 221212211022222. Its totient is φ = 221212211022220.

The previous prime is 221212211022191. The next prime is 221212211022227. The reversal of 221212211022221 is 122220112212122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 118568687655625 + 102643523366596 = 10888925^2 + 10131314^2 .

It is a cyclic number.

It is not a de Polignac number, because 221212211022221 - 2⁶ = 221212211022157 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 (221212211022227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110606105511110 + 110606105511111.

It is an arithmetic number, because the mean of its divisors is an integer number (110606105511111).

Almost surely, 2^{221212211022221} is an apocalyptic number.

It is an amenable number.

221212211022221 is a deficient number, since it is larger than the sum of its proper divisors (1).

221212211022221 is an equidigital number, since it uses as much as digits as its factorization.

221212211022221 is an odious number, because the sum of its binary digits is odd.

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

Adding to 221212211022221 its reverse (122220112212122), we get a palindrome (343432323234343).

The spelling of 221212211022221 in words is "two hundred twenty-one trillion, two hundred twelve billion, two hundred eleven million, twenty-two thousand, two hundred twenty-one".