138809 has 4 divisors (see below), whose sum is σ = 151440. Its totient is φ = 126180.

The previous prime is 138799. The next prime is 138821. The reversal of 138809 is 908831.

It is a happy number.

138809 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, 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 138809 - 2⁴ = 138793 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (138829) 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, 6299 + ... + 6320.

It is an arithmetic number, because the mean of its divisors is an integer number (37860).

2¹³⁸⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

138809 is a deficient number, since it is larger than the sum of its proper divisors (12631).

138809 is a wasteful number, since it uses less digits than its factorization.

138809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12630.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 138809 is about 372.5707986410. The cubic root of 138809 is about 51.7772771941. Note that the first 3 decimals are identical.

The spelling of 138809 in words is "one hundred thirty-eight thousand, eight hundred nine".