121221211121 has 2 divisors, whose sum is σ = 121221211122. Its totient is φ = 121221211120.

The previous prime is 121221211091. The next prime is 121221211123. The reversal of 121221211121 is 121112122121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 87284202721 + 33937008400 = 295439^2 + 184220^2 .

It is an emirp because it is prime and its reverse (121112122121) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121221211121 is a prime.

Together with 121221211123, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 121221211121.

It is not a weakly prime, because it can be changed into another prime (121221211123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60610605560 + 60610605561.

It is an arithmetic number, because the mean of its divisors is an integer number (60610605561).

Almost surely, 2^121221211121 is an apocalyptic number.

It is an amenable number.

121221211121 is a deficient number, since it is larger than the sum of its proper divisors (1).

121221211121 is an equidigital number, since it uses as much as digits as its factorization.

121221211121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 32, while the sum is 17.

Adding to 121221211121 its reverse (121112122121), we get a palindrome (242333333242).

The spelling of 121221211121 in words is "one hundred twenty-one billion, two hundred twenty-one million, two hundred eleven thousand, one hundred twenty-one".