138432478 has 4 divisors (see below), whose sum is σ = 207648720. Its totient is φ = 69216238.

The previous prime is 138432451. The next prime is 138432487. The reversal of 138432478 is 874234831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 874234831 = 10177 ⋅85903.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 138432478.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34608118 + ... + 34608121.

It is an arithmetic number, because the mean of its divisors is an integer number (51912180).

Almost surely, 2^138432478 is an apocalyptic number.

138432478 is a deficient number, since it is larger than the sum of its proper divisors (69216242).

138432478 is an equidigital number, since it uses as much as digits as its factorization.

138432478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69216241.

The product of its digits is 129024, while the sum is 40.

The square root of 138432478 is about 11765.7332113218. The cubic root of 138432478 is about 517.3041919091.

The spelling of 138432478 in words is "one hundred thirty-eight million, four hundred thirty-two thousand, four hundred seventy-eight".