18439009 has 2 divisors, whose sum is σ = 18439010. Its totient is φ = 18439008.

The previous prime is 18439007. The next prime is 18439039. The reversal of 18439009 is 90093481.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14326225 + 4112784 = 3785^2 + 2028^2 .

It is a cyclic number.

It is not a de Polignac number, because 18439009 - 2¹ = 18439007 is a prime.

Together with 18439007, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (18439007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9219504 + 9219505.

It is an arithmetic number, because the mean of its divisors is an integer number (9219505).

Almost surely, 2^18439009 is an apocalyptic number.

It is an amenable number.

18439009 is a deficient number, since it is larger than the sum of its proper divisors (1).

18439009 is an equidigital number, since it uses as much as digits as its factorization.

18439009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 18439009 is about 4294.0667204877. The cubic root of 18439009 is about 264.1876583190.

It can be divided in two parts, 184 and 39009, that added together give a palindrome (39193).

The spelling of 18439009 in words is "eighteen million, four hundred thirty-nine thousand, nine".