138640539 has 4 divisors (see below), whose sum is σ = 184854056. Its totient is φ = 92427024.

The previous prime is 138640531. The next prime is 138640543. The reversal of 138640539 is 935046831.

138640539 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.

It is not a de Polignac number, because 138640539 - 2³ = 138640531 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 138640497 and 138640506.

It is not an unprimeable number, because it can be changed into a prime (138640531) 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, 23106754 + ... + 23106759.

It is an arithmetic number, because the mean of its divisors is an integer number (46213514).

Almost surely, 2^138640539 is an apocalyptic number.

138640539 is a deficient number, since it is larger than the sum of its proper divisors (46213517).

138640539 is an equidigital number, since it uses as much as digits as its factorization.

138640539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46213516.

The product of its (nonzero) digits is 77760, while the sum is 39.

The square root of 138640539 is about 11774.5717119562. The cubic root of 138640539 is about 517.5632278226.

The spelling of 138640539 in words is "one hundred thirty-eight million, six hundred forty thousand, five hundred thirty-nine".