18233218 has 4 divisors (see below), whose sum is σ = 27349830. Its totient is φ = 9116608.

The previous prime is 18233213. The next prime is 18233221. The reversal of 18233218 is 81233281.

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., 15944049 + 2289169 = 3993^2 + 1513^2 .

It is not an unprimeable number, because it can be changed into a prime (18233213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4558303 + ... + 4558306.

Almost surely, 2^18233218 is an apocalyptic number.

18233218 is a deficient number, since it is larger than the sum of its proper divisors (9116612).

18233218 is an equidigital number, since it uses as much as digits as its factorization.

18233218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9116611.

The product of its digits is 2304, while the sum is 28.

The square root of 18233218 is about 4270.0372363716. The cubic root of 18233218 is about 263.2011453558.

Adding to 18233218 its reverse (81233281), we get a palindrome (99466499).

It can be divided in two parts, 1823 and 3218, that added together give a square (5041 = 71²).

The spelling of 18233218 in words is "eighteen million, two hundred thirty-three thousand, two hundred eighteen".