18319919 has 2 divisors, whose sum is σ = 18319920. Its totient is φ = 18319918.

The previous prime is 18319901. The next prime is 18319963. The reversal of 18319919 is 91991381.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (91991381) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18319919 - 2²⁴ = 1542703 is a prime.

It is a super-2 number, since 2×18319919² = 671238864333122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18319969) 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, 9159959 + 9159960.

It is an arithmetic number, because the mean of its divisors is an integer number (9159960).

Almost surely, 2^18319919 is an apocalyptic number.

18319919 is a deficient number, since it is larger than the sum of its proper divisors (1).

18319919 is an equidigital number, since it uses as much as digits as its factorization.

18319919 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17496, while the sum is 41.

The square root of 18319919 is about 4280.1774495925. The cubic root of 18319919 is about 263.6176695172.

It can be divided in two parts, 183 and 19919, that added together give a palindrome (20102).

The spelling of 18319919 in words is "eighteen million, three hundred nineteen thousand, nine hundred nineteen".