135125209 has 4 divisors (see below), whose sum is σ = 135204304. Its totient is φ = 135046116.

The previous prime is 135125183. The next prime is 135125227. The reversal of 135125209 is 902521531.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 902521531 = 457 ⋅1974883.

It is a cyclic number.

It is not a de Polignac number, because 135125209 - 2⁹ = 135124697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (135125509) 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 in 3 ways as a sum of consecutive naturals, for example, 36927 + ... + 40420.

It is an arithmetic number, because the mean of its divisors is an integer number (33801076).

Almost surely, 2^135125209 is an apocalyptic number.

It is an amenable number.

135125209 is a deficient number, since it is larger than the sum of its proper divisors (79095).

135125209 is an equidigital number, since it uses as much as digits as its factorization.

135125209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79094.

The product of its (nonzero) digits is 2700, while the sum is 28.

The square root of 135125209 is about 11624.3369273262. The cubic root of 135125209 is about 513.1513308329.

It can be divided in two parts, 13512 and 5209, that added together give a triangular number (18721 = T₁₉₃).

The spelling of 135125209 in words is "one hundred thirty-five million, one hundred twenty-five thousand, two hundred nine".