138539918 has 12 divisors (see below), whose sum is σ = 228419520. Its totient is φ = 62972580.

The previous prime is 138539917. The next prime is 138539939. The reversal of 138539918 is 819935831.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138539917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 285998 + ... + 286481.

It is an arithmetic number, because the mean of its divisors is an integer number (19034960).

Almost surely, 2^138539918 is an apocalyptic number.

138539918 is a deficient number, since it is larger than the sum of its proper divisors (89879602).

138539918 is a wasteful number, since it uses less digits than its factorization.

138539918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 572503 (or 572492 counting only the distinct ones).

The product of its digits is 233280, while the sum is 47.

The square root of 138539918 is about 11770.2981270654. The cubic root of 138539918 is about 517.4379870770.

The spelling of 138539918 in words is "one hundred thirty-eight million, five hundred thirty-nine thousand, nine hundred eighteen".