138423 has 4 divisors (see below), whose sum is σ = 184568. Its totient is φ = 92280.

The previous prime is 138407. The next prime is 138427. The reversal of 138423 is 324831.

It is a happy number.

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

It is not a de Polignac number, because 138423 - 2⁴ = 138407 is a prime.

It is a D-number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 138423.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138427) 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, 23068 + ... + 23073.

It is an arithmetic number, because the mean of its divisors is an integer number (46142).

2¹³⁸⁴²³ is an apocalyptic number.

138423 is a deficient number, since it is larger than the sum of its proper divisors (46145).

138423 is an equidigital number, since it uses as much as digits as its factorization.

138423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46144.

The product of its digits is 576, while the sum is 21.

The square root of 138423 is about 372.0524156621. The cubic root of 138423 is about 51.7292385621.

It can be divided in two parts, 138 and 423, that added together give a triangular number (561 = T₃₃).

The spelling of 138423 in words is "one hundred thirty-eight thousand, four hundred twenty-three".