18161818 has 8 divisors (see below), whose sum is σ = 27266400. Its totient is φ = 9073020.

The previous prime is 18161809. The next prime is 18161839. The reversal of 18161818 is 81816181.

It is a sphenic number, since it is the product of 3 distinct primes.

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

18161818 is a modest number, since divided by 1818 gives 1816 as remainder.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 448 + ... + 6043.

It is an arithmetic number, because the mean of its divisors is an integer number (3408300).

Almost surely, 2^18161818 is an apocalyptic number.

18161818 is a deficient number, since it is larger than the sum of its proper divisors (9104582).

18161818 is a wasteful number, since it uses less digits than its factorization.

18161818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7892.

The product of its digits is 3072, while the sum is 34.

The square root of 18161818 is about 4261.6684526134. The cubic root of 18161818 is about 262.8571368654.

Adding to 18161818 its reverse (81816181), we get a palindrome (99977999).

The spelling of 18161818 in words is "eighteen million, one hundred sixty-one thousand, eight hundred eighteen".