18320403 has 4 divisors (see below), whose sum is σ = 24427208. Its totient is φ = 12213600.

The previous prime is 18320387. The next prime is 18320417. The reversal of 18320403 is 30402381.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 30402381 = 3 ⋅10134127.

It is not a de Polignac number, because 18320403 - 2⁴ = 18320387 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18320403.

It is not an unprimeable number, because it can be changed into a prime (18324403) 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 in 3 ways as a sum of consecutive naturals, for example, 3053398 + ... + 3053403.

It is an arithmetic number, because the mean of its divisors is an integer number (6106802).

Almost surely, 2^18320403 is an apocalyptic number.

18320403 is a deficient number, since it is larger than the sum of its proper divisors (6106805).

18320403 is an equidigital number, since it uses as much as digits as its factorization.

18320403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6106804.

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 18320403 is about 4280.2339889310. The cubic root of 18320403 is about 263.6199910309.

Adding to 18320403 its reverse (30402381), we get a palindrome (48722784).

The spelling of 18320403 in words is "eighteen million, three hundred twenty thousand, four hundred three".