18190818 has 20 divisors (see below), whose sum is σ = 40761270. Its totient is φ = 6063552.

The previous prime is 18190811. The next prime is 18190841. The reversal of 18190818 is 81809181.

18190818 is nontrivially palindromic in base 12.

It can be written as a sum of positive squares in only one way, i.e., 9529569 + 8661249 = 3087^2 + 2943^2 .

It is not an unprimeable number, because it can be changed into a prime (18190811) 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 in 9 ways as a sum of consecutive naturals, for example, 55983 + ... + 56306.

Almost surely, 2^18190818 is an apocalyptic number.

18190818 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

18190818 is an abundant number, since it is smaller than the sum of its proper divisors (22570452).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18190818 is a wasteful number, since it uses less digits than its factorization.

18190818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112303 (or 112294 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 36.

The square root of 18190818 is about 4265.0695187769. The cubic root of 18190818 is about 262.9969687420.

Adding to 18190818 its reverse (81809181), we get a palindrome (99999999).

The spelling of 18190818 in words is "eighteen million, one hundred ninety thousand, eight hundred eighteen".