18108985 has 4 divisors (see below), whose sum is σ = 21730788. Its totient is φ = 14487184.

The previous prime is 18108983. The next prime is 18108989. The reversal of 18108985 is 58980181.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8173881 + 9935104 = 2859^2 + 3152^2 .

It is a cyclic number.

It is not a de Polignac number, because 18108985 - 2¹ = 18108983 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18108983) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1810894 + ... + 1810903.

It is an arithmetic number, because the mean of its divisors is an integer number (5432697).

Almost surely, 2^18108985 is an apocalyptic number.

It is an amenable number.

18108985 is a deficient number, since it is larger than the sum of its proper divisors (3621803).

18108985 is an equidigital number, since it uses as much as digits as its factorization.

18108985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3621802.

The product of its (nonzero) digits is 23040, while the sum is 40.

The square root of 18108985 is about 4255.4653094579. The cubic root of 18108985 is about 262.6020041971.

The spelling of 18108985 in words is "eighteen million, one hundred eight thousand, nine hundred eighty-five".