135438521 has 2 divisors, whose sum is σ = 135438522. Its totient is φ = 135438520.

The previous prime is 135438491. The next prime is 135438529. The reversal of 135438521 is 125834531.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 135396496 + 42025 = 11636^2 + 205^2 .

It is an emirp because it is prime and its reverse (125834531) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-135438521 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (135438529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67719260 + 67719261.

It is an arithmetic number, because the mean of its divisors is an integer number (67719261).

Almost surely, 2^135438521 is an apocalyptic number.

It is an amenable number.

135438521 is a deficient number, since it is larger than the sum of its proper divisors (1).

135438521 is an equidigital number, since it uses as much as digits as its factorization.

135438521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14400, while the sum is 32.

The square root of 135438521 is about 11637.8056780477. The cubic root of 135438521 is about 513.5476357804.

The spelling of 135438521 in words is "one hundred thirty-five million, four hundred thirty-eight thousand, five hundred twenty-one".