138549839 has 4 divisors (see below), whose sum is σ = 140447856. Its totient is φ = 136651824.

The previous prime is 138549833. The next prime is 138549857. The reversal of 138549839 is 938945831.

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

It is a cyclic number.

It is not a de Polignac number, because 138549839 - 2²⁰ = 137501263 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138549833) 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, 948899 + ... + 949044.

It is an arithmetic number, because the mean of its divisors is an integer number (35111964).

Almost surely, 2^138549839 is an apocalyptic number.

138549839 is a deficient number, since it is larger than the sum of its proper divisors (1898017).

138549839 is an equidigital number, since it uses as much as digits as its factorization.

138549839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1898016.

The product of its digits is 933120, while the sum is 50.

The square root of 138549839 is about 11770.7195616921. The cubic root of 138549839 is about 517.4503382218.

It can be divided in two parts, 138549 and 839, that multiplied together give a palindrome (116242611).

The spelling of 138549839 in words is "one hundred thirty-eight million, five hundred forty-nine thousand, eight hundred thirty-nine".