138278138 has 4 divisors (see below), whose sum is σ = 207417210. Its totient is φ = 69139068.

The previous prime is 138278071. The next prime is 138278141. The reversal of 138278138 is 831872831.

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

It can be written as a sum of positive squares in only one way, i.e., 120275089 + 18003049 = 10967^2 + 4243^2 .

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 138278095 and 138278104.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34569533 + ... + 34569536.

Almost surely, 2^138278138 is an apocalyptic number.

138278138 is a deficient number, since it is larger than the sum of its proper divisors (69139072).

138278138 is an equidigital number, since it uses as much as digits as its factorization.

138278138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69139071.

The product of its digits is 64512, while the sum is 41.

The square root of 138278138 is about 11759.1725049002. The cubic root of 138278138 is about 517.1118709059. Note that the first 3 decimals are identical.

The spelling of 138278138 in words is "one hundred thirty-eight million, two hundred seventy-eight thousand, one hundred thirty-eight".