138109 has 4 divisors (see below), whose sum is σ = 139104. Its totient is φ = 137116.

The previous prime is 138107. The next prime is 138113. The reversal of 138109 is 901831.

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, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 901831 = 7 ⋅128833.

It is a cyclic number.

It is not a de Polignac number, because 138109 - 2¹ = 138107 is a prime.

It is a Duffinian number.

138109 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 138109.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 247 + ... + 580.

It is an arithmetic number, because the mean of its divisors is an integer number (34776).

2¹³⁸¹⁰⁹ is an apocalyptic number.

It is an amenable number.

138109 is a deficient number, since it is larger than the sum of its proper divisors (995).

138109 is an equidigital number, since it uses as much as digits as its factorization.

138109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 994.

The product of its (nonzero) digits is 216, while the sum is 22.

The square root of 138109 is about 371.6301925302. The cubic root of 138109 is about 51.6900945896.

The spelling of 138109 in words is "one hundred thirty-eight thousand, one hundred nine".