18216449 has 2 divisors, whose sum is σ = 18216450. Its totient is φ = 18216448.

The previous prime is 18216433. The next prime is 18216463. The reversal of 18216449 is 94461281.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18215824 + 625 = 4268^2 + 25^2 .

It is an emirp because it is prime and its reverse (94461281) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18216449 - 2⁴ = 18216433 is a prime.

It is not a weakly prime, because it can be changed into another prime (18216409) 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, 9108224 + 9108225.

It is an arithmetic number, because the mean of its divisors is an integer number (9108225).

Almost surely, 2^18216449 is an apocalyptic number.

It is an amenable number.

18216449 is a deficient number, since it is larger than the sum of its proper divisors (1).

18216449 is an equidigital number, since it uses as much as digits as its factorization.

18216449 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13824, while the sum is 35.

The square root of 18216449 is about 4268.0732186784. The cubic root of 18216449 is about 263.1204323451.

The spelling of 18216449 in words is "eighteen million, two hundred sixteen thousand, four hundred forty-nine".