18238009 has 2 divisors, whose sum is σ = 18238010. Its totient is φ = 18238008.

The previous prime is 18238007. The next prime is 18238039. The reversal of 18238009 is 90083281.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17197609 + 1040400 = 4147^2 + 1020^2 .

It is a cyclic number.

It is not a de Polignac number, because 18238009 - 2¹ = 18238007 is a prime.

Together with 18238007, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (18238001) 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 as a sum of consecutive naturals, namely, 9119004 + 9119005.

It is an arithmetic number, because the mean of its divisors is an integer number (9119005).

Almost surely, 2^18238009 is an apocalyptic number.

It is an amenable number.

18238009 is a deficient number, since it is larger than the sum of its proper divisors (1).

18238009 is an equidigital number, since it uses as much as digits as its factorization.

18238009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 18238009 is about 4270.5982016575. The cubic root of 18238009 is about 263.2241964387.

The spelling of 18238009 in words is "eighteen million, two hundred thirty-eight thousand, nine".