138439 has 4 divisors (see below), whose sum is σ = 158224. Its totient is φ = 118656.

The previous prime is 138433. The next prime is 138449. The reversal of 138439 is 934831.

138439 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 138439 - 2⁵ = 138407 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138433) 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, 9882 + ... + 9895.

It is an arithmetic number, because the mean of its divisors is an integer number (39556).

2¹³⁸⁴³⁹ is an apocalyptic number.

138439 is a deficient number, since it is larger than the sum of its proper divisors (19785).

138439 is an equidigital number, since it uses as much as digits as its factorization.

138439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19784.

The product of its digits is 2592, while the sum is 28.

The square root of 138439 is about 372.0739173874. The cubic root of 138439 is about 51.7312315737.

The spelling of 138439 in words is "one hundred thirty-eight thousand, four hundred thirty-nine".