18918019 has 2 divisors, whose sum is σ = 18918020. Its totient is φ = 18918018.

The previous prime is 18918013. The next prime is 18918043. The reversal of 18918019 is 91081981.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (91081981) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18918019 - 2²³ = 10529411 is a prime.

It is a super-2 number, since 2×18918019² = 715782885768722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18918013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9459009 + 9459010.

It is an arithmetic number, because the mean of its divisors is an integer number (9459010).

Almost surely, 2^18918019 is an apocalyptic number.

18918019 is a deficient number, since it is larger than the sum of its proper divisors (1).

18918019 is an equidigital number, since it uses as much as digits as its factorization.

18918019 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 37.

The square root of 18918019 is about 4349.4849120327. The cubic root of 18918019 is about 266.4558251812.

The spelling of 18918019 in words is "eighteen million, nine hundred eighteen thousand, nineteen".