18409393 has 2 divisors, whose sum is σ = 18409394. Its totient is φ = 18409392.

The previous prime is 18409367. The next prime is 18409409. The reversal of 18409393 is 39390481.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14500864 + 3908529 = 3808^2 + 1977^2 .

It is a cyclic number.

It is not a de Polignac number, because 18409393 - 2¹⁷ = 18278321 is a prime.

It is not a weakly prime, because it can be changed into another prime (18409333) 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, 9204696 + 9204697.

It is an arithmetic number, because the mean of its divisors is an integer number (9204697).

Almost surely, 2^18409393 is an apocalyptic number.

It is an amenable number.

18409393 is a deficient number, since it is larger than the sum of its proper divisors (1).

18409393 is an equidigital number, since it uses as much as digits as its factorization.

18409393 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23328, while the sum is 37.

The square root of 18409393 is about 4290.6168554183. The cubic root of 18409393 is about 264.0461399689.

The spelling of 18409393 in words is "eighteen million, four hundred nine thousand, three hundred ninety-three".