18785009 has 2 divisors, whose sum is σ = 18785010. Its totient is φ = 18785008.

The previous prime is 18784999. The next prime is 18785021. The reversal of 18785009 is 90058781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17247409 + 1537600 = 4153^2 + 1240^2 .

It is an emirp because it is prime and its reverse (90058781) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18785009 - 2⁴ = 18784993 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (18785059) 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, 9392504 + 9392505.

It is an arithmetic number, because the mean of its divisors is an integer number (9392505).

Almost surely, 2^18785009 is an apocalyptic number.

It is an amenable number.

18785009 is a deficient number, since it is larger than the sum of its proper divisors (1).

18785009 is an equidigital number, since it uses as much as digits as its factorization.

18785009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20160, while the sum is 38.

The square root of 18785009 is about 4334.1676248156. The cubic root of 18785009 is about 265.8298844449.

The spelling of 18785009 in words is "eighteen million, seven hundred eighty-five thousand, nine".