138539636 has 12 divisors (see below), whose sum is σ = 248082912. Its totient is φ = 67658808.

The previous prime is 138539633. The next prime is 138539657. The reversal of 138539636 is 636935831.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138539633) 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, 402560 + ... + 402903.

It is an arithmetic number, because the mean of its divisors is an integer number (20673576).

Almost surely, 2^138539636 is an apocalyptic number.

It is an amenable number.

138539636 is a deficient number, since it is larger than the sum of its proper divisors (109543276).

138539636 is a wasteful number, since it uses less digits than its factorization.

138539636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 805510 (or 805508 counting only the distinct ones).

The product of its digits is 349920, while the sum is 44.

The square root of 138539636 is about 11770.2861477536. The cubic root of 138539636 is about 517.4376359926.

The spelling of 138539636 in words is "one hundred thirty-eight million, five hundred thirty-nine thousand, six hundred thirty-six".