18318719 has 4 divisors (see below), whose sum is σ = 18356520. Its totient is φ = 18280920.

The previous prime is 18318709. The next prime is 18318779. The reversal of 18318719 is 91781381.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 91781381 = 19 ⋅4830599.

It is a cyclic number.

It is not a de Polignac number, because 18318719 - 2⁸ = 18318463 is a prime.

It is a super-2 number, since 2×18318719² = 671150931601922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18318709) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18164 + ... + 19145.

It is an arithmetic number, because the mean of its divisors is an integer number (4589130).

Almost surely, 2^18318719 is an apocalyptic number.

18318719 is a deficient number, since it is larger than the sum of its proper divisors (37801).

18318719 is an equidigital number, since it uses as much as digits as its factorization.

18318719 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37800.

The product of its digits is 12096, while the sum is 38.

The square root of 18318719 is about 4280.0372661929. The cubic root of 18318719 is about 263.6119135218.

The spelling of 18318719 in words is "eighteen million, three hundred eighteen thousand, seven hundred nineteen".