12212121220021 has 2 divisors, whose sum is σ = 12212121220022. Its totient is φ = 12212121220020.

The previous prime is 12212121219989. The next prime is 12212121220037. The reversal of 12212121220021 is 12002212121221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11104796452996 + 1107324767025 = 3332386^2 + 1052295^2 .

It is a cyclic number.

It is not a de Polignac number, because 12212121220021 - 2⁵ = 12212121219989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12212121220051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6106060610010 + 6106060610011.

It is an arithmetic number, because the mean of its divisors is an integer number (6106060610011).

Almost surely, 2^{12212121220021} is an apocalyptic number.

It is an amenable number.

12212121220021 is a deficient number, since it is larger than the sum of its proper divisors (1).

12212121220021 is an equidigital number, since it uses as much as digits as its factorization.

12212121220021 is an odious number, because the sum of its binary digits is odd.

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

Adding to 12212121220021 its reverse (12002212121221), we get a palindrome (24214333341242).

The spelling of 12212121220021 in words is "twelve trillion, two hundred twelve billion, one hundred twenty-one million, two hundred twenty thousand, twenty-one".