18185998 has 4 divisors (see below), whose sum is σ = 27279000. Its totient is φ = 9092998.

The previous prime is 18185977. The next prime is 18186017. The reversal of 18185998 is 89958181.

It is a semiprime because it is the product of two primes.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4546498 + ... + 4546501.

It is an arithmetic number, because the mean of its divisors is an integer number (6819750).

Almost surely, 2^18185998 is an apocalyptic number.

18185998 is a deficient number, since it is larger than the sum of its proper divisors (9093002).

18185998 is an equidigital number, since it uses as much as digits as its factorization.

18185998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9093001.

The product of its digits is 207360, while the sum is 49.

The square root of 18185998 is about 4264.5044260734. The cubic root of 18185998 is about 262.9737380226.

The spelling of 18185998 in words is "eighteen million, one hundred eighty-five thousand, nine hundred ninety-eight".