138878438 has 4 divisors (see below), whose sum is σ = 208317660. Its totient is φ = 69439218.

The previous prime is 138878417. The next prime is 138878447. The reversal of 138878438 is 834878831.

138878438 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 834878831 = 277 ⋅3014003.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34719608 + ... + 34719611.

It is an arithmetic number, because the mean of its divisors is an integer number (52079415).

Almost surely, 2^138878438 is an apocalyptic number.

138878438 is a deficient number, since it is larger than the sum of its proper divisors (69439222).

138878438 is an equidigital number, since it uses as much as digits as its factorization.

138878438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69439221.

The product of its digits is 1032192, while the sum is 50.

The square root of 138878438 is about 11784.6696177704. The cubic root of 138878438 is about 517.8590946632.

The spelling of 138878438 in words is "one hundred thirty-eight million, eight hundred seventy-eight thousand, four hundred thirty-eight".