135209 has 2 divisors, whose sum is σ = 135210. Its totient is φ = 135208.

The previous prime is 135197. The next prime is 135211. The reversal of 135209 is 902531.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 105625 + 29584 = 325^2 + 172^2 .

It is a cyclic number.

It is not a de Polignac number, because 135209 - 2⁴ = 135193 is a prime.

Together with 135211, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (135409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 67604 + 67605.

It is an arithmetic number, because the mean of its divisors is an integer number (67605).

2¹³⁵²⁰⁹ is an apocalyptic number.

It is an amenable number.

135209 is a deficient number, since it is larger than the sum of its proper divisors (1).

135209 is an equidigital number, since it uses as much as digits as its factorization.

135209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 270, while the sum is 20.

The square root of 135209 is about 367.7077643999. The cubic root of 135209 is about 51.3257377116.

The spelling of 135209 in words is "one hundred thirty-five thousand, two hundred nine".