18105818 has 4 divisors (see below), whose sum is σ = 27158730. Its totient is φ = 9052908.

The previous prime is 18105817. The next prime is 18105823. The reversal of 18105818 is 81850181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 81850181 = 7 ⋅11692883.

It can be written as a sum of positive squares in only one way, i.e., 17197609 + 908209 = 4147^2 + 953^2 .

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (18105811) 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, 4526453 + ... + 4526456.

Almost surely, 2^18105818 is an apocalyptic number.

18105818 is a deficient number, since it is larger than the sum of its proper divisors (9052912).

18105818 is an equidigital number, since it uses as much as digits as its factorization.

18105818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9052911.

The product of its (nonzero) digits is 2560, while the sum is 32.

The square root of 18105818 is about 4255.0931834685. The cubic root of 18105818 is about 262.5866948716.

Adding to 18105818 its reverse (81850181), we get a palindrome (99955999).

The spelling of 18105818 in words is "eighteen million, one hundred five thousand, eight hundred eighteen".