138309 has 4 divisors (see below), whose sum is σ = 184416. Its totient is φ = 92204.

The previous prime is 138289. The next prime is 138311. The reversal of 138309 is 903831.

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.

It is a cyclic number.

It is not a de Polignac number, because 138309 - 2⁷ = 138181 is a prime.

It is a D-number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23049 + ... + 23054.

It is an arithmetic number, because the mean of its divisors is an integer number (46104).

2¹³⁸³⁰⁹ is an apocalyptic number.

It is an amenable number.

138309 is a deficient number, since it is larger than the sum of its proper divisors (46107).

138309 is an equidigital number, since it uses as much as digits as its factorization.

138309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46106.

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 138309 is about 371.8991798862. The cubic root of 138309 is about 51.7150339073.

The spelling of 138309 in words is "one hundred thirty-eight thousand, three hundred nine".