18098809 has 4 divisors (see below), whose sum is σ = 18588004. Its totient is φ = 17609616.

The previous prime is 18098797. The next prime is 18098819. The reversal of 18098809 is 90889081.

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 10061584 + 8037225 = 3172^2 + 2835^2 .

It is a cyclic number.

It is not a de Polignac number, because 18098809 - 2¹³ = 18090617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18098819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 244542 + ... + 244615.

It is an arithmetic number, because the mean of its divisors is an integer number (4647001).

Almost surely, 2^18098809 is an apocalyptic number.

It is an amenable number.

18098809 is a deficient number, since it is larger than the sum of its proper divisors (489195).

18098809 is an equidigital number, since it uses as much as digits as its factorization.

18098809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 489194.

The product of its (nonzero) digits is 41472, while the sum is 43.

The square root of 18098809 is about 4254.2695025116. The cubic root of 18098809 is about 262.5528069121.

It can be divided in two parts, 180 and 98809, that added together give a palindrome (98989).

The spelling of 18098809 in words is "eighteen million, ninety-eight thousand, eight hundred nine".