18181018 has 4 divisors (see below), whose sum is σ = 27271530. Its totient is φ = 9090508.

The previous prime is 18181013. The next prime is 18181021. The reversal of 18181018 is 81018181.

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., 17749369 + 431649 = 4213^2 + 657^2 .

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 (18181013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4545253 + ... + 4545256.

Almost surely, 2^18181018 is an apocalyptic number.

18181018 is a deficient number, since it is larger than the sum of its proper divisors (9090512).

18181018 is an equidigital number, since it uses as much as digits as its factorization.

18181018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9090511.

The product of its (nonzero) digits is 512, while the sum is 28.

The square root of 18181018 is about 4263.9204964446. The cubic root of 18181018 is about 262.9497318472.

Adding to 18181018 its reverse (81018181), we get a palindrome (99199199).

The spelling of 18181018 in words is "eighteen million, one hundred eighty-one thousand, eighteen".