135137670721 has 2 divisors, whose sum is σ = 135137670722. Its totient is φ = 135137670720.

The previous prime is 135137670713. The next prime is 135137670727. The reversal of 135137670721 is 127076731531.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 104209524225 + 30928146496 = 322815^2 + 175864^2 .

It is an emirp because it is prime and its reverse (127076731531) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 135137670721 - 2³ = 135137670713 is a prime.

It is not a weakly prime, because it can be changed into another prime (135137670727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67568835360 + 67568835361.

It is an arithmetic number, because the mean of its divisors is an integer number (67568835361).

Almost surely, 2^135137670721 is an apocalyptic number.

It is an amenable number.

135137670721 is a deficient number, since it is larger than the sum of its proper divisors (1).

135137670721 is an equidigital number, since it uses as much as digits as its factorization.

135137670721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 185220, while the sum is 43.

The spelling of 135137670721 in words is "one hundred thirty-five billion, one hundred thirty-seven million, six hundred seventy thousand, seven hundred twenty-one".