18431018 has 4 divisors (see below), whose sum is σ = 27646530. Its totient is φ = 9215508.

The previous prime is 18431011. The next prime is 18431041. The reversal of 18431018 is 81013481.

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., 18207289 + 223729 = 4267^2 + 473^2 .

It is not an unprimeable number, because it can be changed into a prime (18431011) 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, 4607753 + ... + 4607756.

Almost surely, 2^18431018 is an apocalyptic number.

18431018 is a deficient number, since it is larger than the sum of its proper divisors (9215512).

18431018 is an equidigital number, since it uses as much as digits as its factorization.

18431018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9215511.

The product of its (nonzero) digits is 768, while the sum is 26.

The square root of 18431018 is about 4293.1361497162. The cubic root of 18431018 is about 264.1494887221.

Adding to 18431018 its reverse (81013481), we get a palindrome (99444499).

The spelling of 18431018 in words is "eighteen million, four hundred thirty-one thousand, eighteen".