135220121 has 2 divisors, whose sum is σ = 135220122. Its totient is φ = 135220120.

The previous prime is 135220097. The next prime is 135220123. The reversal of 135220121 is 121022531.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 126810121 + 8410000 = 11261^2 + 2900^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-135220121 is a prime.

It is a super-2 number, since 2×135220121² = 36568962246509282, which contains 22 as substring.

Together with 135220123, 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 135220121.

It is not a weakly prime, because it can be changed into another prime (135220123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67610060 + 67610061.

It is an arithmetic number, because the mean of its divisors is an integer number (67610061).

Almost surely, 2^135220121 is an apocalyptic number.

It is an amenable number.

135220121 is a deficient number, since it is larger than the sum of its proper divisors (1).

135220121 is an equidigital number, since it uses as much as digits as its factorization.

135220121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 135220121 is about 11628.4186801130. The cubic root of 135220121 is about 513.2714486126.

Adding to 135220121 its reverse (121022531), we get a palindrome (256242652).

The spelling of 135220121 in words is "one hundred thirty-five million, two hundred twenty thousand, one hundred twenty-one".