128278138 has 4 divisors (see below), whose sum is σ = 192417210. Its totient is φ = 64139068.

The previous prime is 128278097. The next prime is 128278147. The reversal of 128278138 is 831872821.

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., 113784889 + 14493249 = 10667^2 + 3807^2 .

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 128278138.

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, 32069533 + ... + 32069536.

Almost surely, 2^128278138 is an apocalyptic number.

128278138 is a deficient number, since it is larger than the sum of its proper divisors (64139072).

128278138 is an equidigital number, since it uses as much as digits as its factorization.

128278138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64139071.

The product of its digits is 43008, while the sum is 40.

The square root of 128278138 is about 11325.9939078211. The cubic root of 128278138 is about 504.3331891276. Note that the first 3 decimals are identical.

The spelling of 128278138 in words is "one hundred twenty-eight million, two hundred seventy-eight thousand, one hundred thirty-eight".