139391 has 4 divisors (see below), whose sum is σ = 159312. Its totient is φ = 119472.

The previous prime is 139387. The next prime is 139393. The reversal of 139391 is 193931.

139391 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 an emirpimes, since its reverse is a distinct semiprime: 193931 = 89 ⋅2179.

It is a cyclic number.

It is not a de Polignac number, because 139391 - 2² = 139387 is a prime.

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 139391.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 139391.

It is not an unprimeable number, because it can be changed into a prime (139393) 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, 9950 + ... + 9963.

It is an arithmetic number, because the mean of its divisors is an integer number (39828).

2¹³⁹³⁹¹ is an apocalyptic number.

139391 is a deficient number, since it is larger than the sum of its proper divisors (19921).

139391 is an equidigital number, since it uses as much as digits as its factorization.

139391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19920.

The product of its digits is 729, while the sum is 26.

The square root of 139391 is about 373.3510412467. The cubic root of 139391 is about 51.8495404172.

The spelling of 139391 in words is "one hundred thirty-nine thousand, three hundred ninety-one".