138709 has 4 divisors (see below), whose sum is σ = 141120. Its totient is φ = 136300.

The previous prime is 138683. The next prime is 138727. The reversal of 138709 is 907831.

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 138709 - 2⁷ = 138581 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138739) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1117 + ... + 1234.

It is an arithmetic number, because the mean of its divisors is an integer number (35280).

2¹³⁸⁷⁰⁹ is an apocalyptic number.

It is an amenable number.

138709 is a deficient number, since it is larger than the sum of its proper divisors (2411).

138709 is an equidigital number, since it uses as much as digits as its factorization.

138709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2410.

The product of its (nonzero) digits is 1512, while the sum is 28.

The square root of 138709 is about 372.4365717810. The cubic root of 138709 is about 51.7648405087.

The spelling of 138709 in words is "one hundred thirty-eight thousand, seven hundred nine".