138651839 has 4 divisors (see below), whose sum is σ = 142399224. Its totient is φ = 134904456.

The previous prime is 138651817. The next prime is 138651859. The reversal of 138651839 is 938156831.

138651839 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: 938156831 = 11789 ⋅79579.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-138651839 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 138651839.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138651859) 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, 1873637 + ... + 1873710.

It is an arithmetic number, because the mean of its divisors is an integer number (35599806).

Almost surely, 2^138651839 is an apocalyptic number.

138651839 is a deficient number, since it is larger than the sum of its proper divisors (3747385).

138651839 is an equidigital number, since it uses as much as digits as its factorization.

138651839 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3747384.

The product of its digits is 155520, while the sum is 44.

The square root of 138651839 is about 11775.0515497810. The cubic root of 138651839 is about 517.5772888989.

The spelling of 138651839 in words is "one hundred thirty-eight million, six hundred fifty-one thousand, eight hundred thirty-nine".