138439439 has 4 divisors (see below), whose sum is σ = 140709000. Its totient is φ = 136169880.

The previous prime is 138439423. The next prime is 138439447. The reversal of 138439439 is 934934831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 934934831 = 12289 ⋅76079.

It is a cyclic number.

It is not a de Polignac number, because 138439439 - 2⁴ = 138439423 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 138439439.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138432439) 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, 1134689 + ... + 1134810.

It is an arithmetic number, because the mean of its divisors is an integer number (35177250).

Almost surely, 2^138439439 is an apocalyptic number.

138439439 is a deficient number, since it is larger than the sum of its proper divisors (2269561).

138439439 is an equidigital number, since it uses as much as digits as its factorization.

138439439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2269560.

The product of its digits is 279936, while the sum is 44.

The square root of 138439439 is about 11766.0290242715. The cubic root of 138439439 is about 517.3128625481.

The spelling of 138439439 in words is "one hundred thirty-eight million, four hundred thirty-nine thousand, four hundred thirty-nine".