12121220021 has 2 divisors, whose sum is σ = 12121220022. Its totient is φ = 12121220020.

The previous prime is 12121219967. The next prime is 12121220029. The reversal of 12121220021 is 12002212121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9426468100 + 2694751921 = 97090^2 + 51911^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12121220021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 12121219978 and 12121220005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12121220029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6060610010 + 6060610011.

It is an arithmetic number, because the mean of its divisors is an integer number (6060610011).

Almost surely, 2^12121220021 is an apocalyptic number.

It is an amenable number.

12121220021 is a deficient number, since it is larger than the sum of its proper divisors (1).

12121220021 is an equidigital number, since it uses as much as digits as its factorization.

12121220021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 12121220021 its reverse (12002212121), we get a palindrome (24123432142).

The spelling of 12121220021 in words is "twelve billion, one hundred twenty-one million, two hundred twenty thousand, twenty-one".