138478 has 4 divisors (see below), whose sum is σ = 207720. Its totient is φ = 69238.

The previous prime is 138469. The next prime is 138493. The reversal of 138478 is 874831.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

138478 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34618 + ... + 34621.

It is an arithmetic number, because the mean of its divisors is an integer number (51930).

2¹³⁸⁴⁷⁸ is an apocalyptic number.

138478 is a deficient number, since it is larger than the sum of its proper divisors (69242).

138478 is an equidigital number, since it uses as much as digits as its factorization.

138478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69241.

The product of its digits is 5376, while the sum is 31.

The square root of 138478 is about 372.1263226379. The cubic root of 138478 is about 51.7360888962.

It can be divided in two parts, 138 and 478, that added together give a palindrome (616).

The spelling of 138478 in words is "one hundred thirty-eight thousand, four hundred seventy-eight".