138138939 has 14 divisors (see below), whose sum is σ = 207114756. Its totient is φ = 92092140.

The previous prime is 138138899. The next prime is 138138967. The reversal of 138138939 is 939831831.

It is a happy number.

It is not a de Polignac number, because 138138939 - 2¹³ = 138130747 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 138138894 and 138138903.

It is not an unprimeable number, because it can be changed into a prime (138138439) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 94017 + ... + 95474.

Almost surely, 2^138138939 is an apocalyptic number.

138138939 is a deficient number, since it is larger than the sum of its proper divisors (68975817).

138138939 is an frugal number, since it uses more digits than its factorization.

138138939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 189509 (or 189494 counting only the distinct ones).

The product of its digits is 139968, while the sum is 45.

The square root of 138138939 is about 11753.2522733072. The cubic root of 138138939 is about 516.9382941244.

The spelling of 138138939 in words is "one hundred thirty-eight million, one hundred thirty-eight thousand, nine hundred thirty-nine".