18019 has 4 divisors (see below), whose sum is σ = 18544. Its totient is φ = 17496.

The previous prime is 18013. The next prime is 18041. The reversal of 18019 is 91081.

18019 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a 4-Lehmer number, since φ(18019) divides (18019-1)⁴.

It is a cyclic number.

It is not a de Polignac number, because 18019 - 2⁵ = 17987 is a prime.

It is a super-2 number, since 2×18019² = 649368722, which contains 22 as substring.

It is a Duffinian number.

18019 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 17987 and 18005.

It is not an unprimeable number, because it can be changed into a prime (18013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 207 + ... + 280.

It is an arithmetic number, because the mean of its divisors is an integer number (4636).

2¹⁸⁰¹⁹ is an apocalyptic number.

18019 is the 78-th hex number.

18019 is a deficient number, since it is larger than the sum of its proper divisors (525).

18019 is an equidigital number, since it uses as much as digits as its factorization.

18019 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 524.

The product of its (nonzero) digits is 72, while the sum is 19.

The square root of 18019 is about 134.2348687935. The cubic root of 18019 is about 26.2166318266.

The spelling of 18019 in words is "eighteen thousand, nineteen".