138439240 has 16 divisors (see below), whose sum is σ = 311488380. Its totient is φ = 55375680.

The previous prime is 138439229. The next prime is 138439253. The reversal of 138439240 is 42934831.

It can be written as a sum of positive squares in 2 ways, for example, as 138438756 + 484 = 11766^2 + 22^2 .

It is a junction number, because it is equal to n+sod(n) for n = 138439196 and 138439205.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1730451 + ... + 1730530.

Almost surely, 2^138439240 is an apocalyptic number.

138439240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

138439240 is an abundant number, since it is smaller than the sum of its proper divisors (173049140).

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

138439240 is a wasteful number, since it uses less digits than its factorization.

138439240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3460992 (or 3460988 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 34.

The square root of 138439240 is about 11766.0205677196. The cubic root of 138439240 is about 517.3126146773.

The spelling of 138439240 in words is "one hundred thirty-eight million, four hundred thirty-nine thousand, two hundred forty".