18098989 has 4 divisors (see below), whose sum is σ = 18126556. Its totient is φ = 18071424.

The previous prime is 18098923. The next prime is 18099007. The reversal of 18098989 is 98989081.

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 12482089 + 5616900 = 3533^2 + 2370^2 .

It is a cyclic number.

It is not a de Polignac number, because 18098989 - 2¹¹ = 18096941 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18098909) 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, 12774 + ... + 14119.

It is an arithmetic number, because the mean of its divisors is an integer number (4531639).

Almost surely, 2^18098989 is an apocalyptic number.

It is an amenable number.

18098989 is a deficient number, since it is larger than the sum of its proper divisors (27567).

18098989 is an equidigital number, since it uses as much as digits as its factorization.

18098989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27566.

The product of its (nonzero) digits is 373248, while the sum is 52.

The square root of 18098989 is about 4254.2906576773. The cubic root of 18098989 is about 262.5536773073.

The spelling of 18098989 in words is "eighteen million, ninety-eight thousand, nine hundred eighty-nine".