18209449 has 2 divisors, whose sum is σ = 18209450. Its totient is φ = 18209448.

The previous prime is 18209447. The next prime is 18209459. The reversal of 18209449 is 94490281.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17372224 + 837225 = 4168^2 + 915^2 .

It is a cyclic number.

It is not a de Polignac number, because 18209449 - 2¹ = 18209447 is a prime.

Together with 18209447, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (18209447) 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, 9104724 + 9104725.

It is an arithmetic number, because the mean of its divisors is an integer number (9104725).

Almost surely, 2^18209449 is an apocalyptic number.

It is an amenable number.

18209449 is a deficient number, since it is larger than the sum of its proper divisors (1).

18209449 is an equidigital number, since it uses as much as digits as its factorization.

18209449 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20736, while the sum is 37.

The square root of 18209449 is about 4267.2530977199. The cubic root of 18209449 is about 263.0867250989.

The spelling of 18209449 in words is "eighteen million, two hundred nine thousand, four hundred forty-nine".