138138 has 64 divisors (see below), whose sum is σ = 387072. Its totient is φ = 31680.

The previous prime is 138113. The next prime is 138139. The reversal of 138138 is 831831.

138138 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 138138.

It is not an unprimeable number, because it can be changed into a prime (138139) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5995 + ... + 6017.

It is an arithmetic number, because the mean of its divisors is an integer number (6048).

2¹³⁸¹³⁸ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138138, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (193536).

138138 is an abundant number, since it is smaller than the sum of its proper divisors (248934).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

138138 is a wasteful number, since it uses less digits than its factorization.

138138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59.

The product of its digits is 576, while the sum is 24.

The square root of 138138 is about 371.6692077641. The cubic root of 138138 is about 51.6937122825.

Adding to 138138 its reverse (831831), we get a palindrome (969969).

It can be divided in two parts, 138 and 138, that added together give a triangular number (276 = T₂₃).

The spelling of 138138 in words is "one hundred thirty-eight thousand, one hundred thirty-eight".