218278138 has 8 divisors (see below), whose sum is σ = 352603188. Its totient is φ = 100743744.

The previous prime is 218278097. The next prime is 218278153. The reversal of 218278138 is 831872812.

218278138 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 211324369 + 6953769 = 14537^2 + 2637^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 218278138.

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 in 3 ways as a sum of consecutive naturals, for example, 4197631 + ... + 4197682.

Almost surely, 2^218278138 is an apocalyptic number.

218278138 is a deficient number, since it is larger than the sum of its proper divisors (134325050).

218278138 is a wasteful number, since it uses less digits than its factorization.

218278138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8395328.

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

The square root of 218278138 is about 14774.2389990145. The cubic root of 218278138 is about 602.1020143303.

The spelling of 218278138 in words is "two hundred eighteen million, two hundred seventy-eight thousand, one hundred thirty-eight".