18008989 has 2 divisors, whose sum is σ = 18008990. Its totient is φ = 18008988.

The previous prime is 18008917. The next prime is 18008993. The reversal of 18008989 is 98980081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14175225 + 3833764 = 3765^2 + 1958^2 .

It is a cyclic number.

It is not a de Polignac number, because 18008989 - 2¹³ = 18000797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18008189) by changing a digit.

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, 9004494 + 9004495.

It is an arithmetic number, because the mean of its divisors is an integer number (9004495).

Almost surely, 2^18008989 is an apocalyptic number.

It is an amenable number.

18008989 is a deficient number, since it is larger than the sum of its proper divisors (1).

18008989 is an equidigital number, since it uses as much as digits as its factorization.

18008989 is an odious number, because the sum of its binary digits is odd.

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

The square root of 18008989 is about 4243.6999187030. The cubic root of 18008989 is about 262.1177577986.

The spelling of 18008989 in words is "eighteen million, eight thousand, nine hundred eighty-nine".