138739913 has 4 divisors (see below), whose sum is σ = 149412228. Its totient is φ = 128067600.

The previous prime is 138739889. The next prime is 138739927. The reversal of 138739913 is 319937831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 319937831 = 29 ⋅11032339.

It can be written as a sum of positive squares in 2 ways, for example, as 74787904 + 63952009 = 8648^2 + 7997^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138739913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138739313) 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, 5336138 + ... + 5336163.

It is an arithmetic number, because the mean of its divisors is an integer number (37353057).

Almost surely, 2^138739913 is an apocalyptic number.

138739913 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

138739913 is a deficient number, since it is larger than the sum of its proper divisors (10672315).

138739913 is a wasteful number, since it uses less digits than its factorization.

138739913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10672314.

The product of its digits is 122472, while the sum is 44.

The square root of 138739913 is about 11778.7908123033. The cubic root of 138739913 is about 517.6868569934.

The spelling of 138739913 in words is "one hundred thirty-eight million, seven hundred thirty-nine thousand, nine hundred thirteen".