12121220621 has 2 divisors, whose sum is σ = 12121220622. Its totient is φ = 12121220620.

The previous prime is 12121220611. The next prime is 12121220623. The reversal of 12121220621 is 12602212121.

12121220621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11905864996 + 215355625 = 109114^2 + 14675^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12121220621 is a prime.

It is a Sophie Germain prime.

Together with 12121220623, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 12121220593 and 12121220602.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12121220623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6060610310 + 6060610311.

It is an arithmetic number, because the mean of its divisors is an integer number (6060610311).

Almost surely, 2^12121220621 is an apocalyptic number.

It is an amenable number.

12121220621 is a deficient number, since it is larger than the sum of its proper divisors (1).

12121220621 is an equidigital number, since it uses as much as digits as its factorization.

12121220621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 20.

Adding to 12121220621 its reverse (12602212121), we get a palindrome (24723432742).

The spelling of 12121220621 in words is "twelve billion, one hundred twenty-one million, two hundred twenty thousand, six hundred twenty-one".