135137221 has 2 divisors, whose sum is σ = 135137222. Its totient is φ = 135137220.

The previous prime is 135137207. The next prime is 135137231. The reversal of 135137221 is 122731531.

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., 121550625 + 13586596 = 11025^2 + 3686^2 .

It is a cyclic number.

It is not a de Polignac number, because 135137221 - 2⁹ = 135136709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (135137231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67568610 + 67568611.

It is an arithmetic number, because the mean of its divisors is an integer number (67568611).

Almost surely, 2^135137221 is an apocalyptic number.

It is an amenable number.

135137221 is a deficient number, since it is larger than the sum of its proper divisors (1).

135137221 is an equidigital number, since it uses as much as digits as its factorization.

135137221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1260, while the sum is 25.

The square root of 135137221 is about 11624.8535904759. The cubic root of 135137221 is about 513.1665359679.

Adding to 135137221 its reverse (122731531), we get a palindrome (257868752).

The spelling of 135137221 in words is "one hundred thirty-five million, one hundred thirty-seven thousand, two hundred twenty-one".