18200018 has 4 divisors (see below), whose sum is σ = 27300030. Its totient is φ = 9100008.

The previous prime is 18199999. The next prime is 18200033. The reversal of 18200018 is 81000281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 81000281 = 83 ⋅975907.

It can be written as a sum of positive squares in only one way, i.e., 14691889 + 3508129 = 3833^2 + 1873^2 .

It is a Curzon number.

It is an unprimeable number.

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, 4550003 + ... + 4550006.

Almost surely, 2^18200018 is an apocalyptic number.

18200018 is a deficient number, since it is larger than the sum of its proper divisors (9100012).

18200018 is an equidigital number, since it uses as much as digits as its factorization.

18200018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9100011.

The product of its (nonzero) digits is 128, while the sum is 20.

The square root of 18200018 is about 4266.1479111723. The cubic root of 18200018 is about 263.0412981454.

Adding to 18200018 its reverse (81000281), we get a palindrome (99200299).

The spelling of 18200018 in words is "eighteen million, two hundred thousand, eighteen".