218257138 has 24 divisors (see below), whose sum is σ = 361795644. Its totient is φ = 98672640.

The previous prime is 218257129. The next prime is 218257139. The reversal of 218257138 is 831752812.

It can be written as a sum of positive squares in 2 ways, for example, as 213072409 + 5184729 = 14597^2 + 2277^2 .

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 218257097 and 218257106.

It is not an unprimeable number, because it can be changed into a prime (218257139) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 44370 + ... + 49042.

Almost surely, 2^218257138 is an apocalyptic number.

218257138 is a deficient number, since it is larger than the sum of its proper divisors (143538506).

218257138 is a wasteful number, since it uses less digits than its factorization.

218257138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4890 (or 4879 counting only the distinct ones).

The product of its digits is 26880, while the sum is 37.

The square root of 218257138 is about 14773.5282854165. The cubic root of 218257138 is about 602.0827047956.

The spelling of 218257138 in words is "two hundred eighteen million, two hundred fifty-seven thousand, one hundred thirty-eight".