138540840 has 64 divisors (see below), whose sum is σ = 425304000. Its totient is φ = 36083712.

The previous prime is 138540833. The next prime is 138540847. The reversal of 138540840 is 48045831.

It is an interprime number because it is at equal distance from previous prime (138540833) and next prime (138540847).

It is not an unprimeable number, because it can be changed into a prime (138540847) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8265 + ... + 18584.

It is an arithmetic number, because the mean of its divisors is an integer number (6645375).

Almost surely, 2^138540840 is an apocalyptic number.

138540840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

138540840 is an abundant number, since it is smaller than the sum of its proper divisors (286763160).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

138540840 is a wasteful number, since it uses less digits than its factorization.

138540840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26906 (or 26902 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 33.

The square root of 138540840 is about 11770.3372933829. The cubic root of 138540840 is about 517.4391349454.

The spelling of 138540840 in words is "one hundred thirty-eight million, five hundred forty thousand, eight hundred forty".