218321117 has 6 divisors (see below), whose sum is σ = 253965438. Its totient is φ = 187132344.

The previous prime is 218321111. The next prime is 218321119. The reversal of 218321117 is 711123812.

It can be written as a sum of positive squares in only one way, i.e., 111281401 + 107039716 = 10549^2 + 10346^2 .

It is not a de Polignac number, because 218321117 - 2¹⁰ = 218320093 is a prime.

It is a super-2 number, since 2×218321117² = 95328220256255378, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (218321111) 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 5 ways as a sum of consecutive naturals, for example, 2227718 + ... + 2227815.

It is an arithmetic number, because the mean of its divisors is an integer number (42327573).

Almost surely, 2^218321117 is an apocalyptic number.

It is an amenable number.

218321117 is a deficient number, since it is larger than the sum of its proper divisors (35644321).

218321117 is an equidigital number, since it uses as much as digits as its factorization.

218321117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4455547 (or 4455540 counting only the distinct ones).

The product of its digits is 672, while the sum is 26.

The square root of 218321117 is about 14775.6934524238. The cubic root of 218321117 is about 602.1415297309.

Adding to 218321117 its reverse (711123812), we get a palindrome (929444929).

The spelling of 218321117 in words is "two hundred eighteen million, three hundred twenty-one thousand, one hundred seventeen".