138539181 has 32 divisors (see below), whose sum is σ = 206300160. Its totient is φ = 81993600.

The previous prime is 138539179. The next prime is 138539209. The reversal of 138539181 is 181935831.

It is not a de Polignac number, because 138539181 - 2¹ = 138539179 is a prime.

It is a super-2 number, since 2×138539181² = 38386209344301522, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138539131) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 315360 + ... + 315798.

It is an arithmetic number, because the mean of its divisors is an integer number (6446880).

Almost surely, 2^138539181 is an apocalyptic number.

138539181 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

138539181 is a deficient number, since it is larger than the sum of its proper divisors (67760979).

138539181 is a wasteful number, since it uses less digits than its factorization.

138539181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 657.

The product of its digits is 25920, while the sum is 39.

The square root of 138539181 is about 11770.2668194056. The cubic root of 138539181 is about 517.4370695257.

The spelling of 138539181 in words is "one hundred thirty-eight million, five hundred thirty-nine thousand, one hundred eighty-one".