18889 has 4 divisors (see below), whose sum is σ = 20356.
Its totient is φ = 17424.
The previous prime is 18869. The next prime is 18899. The reversal of 18889 is 98881.
18889 is nontrivially palindromic in base 2.
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 98881 = 61 ⋅1621.
It can be written as a sum of positive squares in 2 ways, for example, as 11664 + 7225 = 108^2 + 85^2
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-18889 is a prime.
It is a Duffinian number.
It is a plaindrome in base 10.
It is not an unprimeable number, because it can be changed into a prime (18839) 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, 714 + ... + 739.
It is an arithmetic number, because the mean of its divisors is an integer number (5089).
218889 is an apocalyptic number.
It is an amenable number.
18889 is a deficient number, since it is larger than the sum of its proper divisors (1467).
18889 is a wasteful number, since it uses less digits than its factorization.
18889 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 1466.
The product of its digits is 4608, while the sum is 34.
The square root of 18889 is about 137.4372584127.
The cubic root of 18889 is about 26.6319513542.
The spelling of 18889 in words is "eighteen thousand, eight hundred eighty-nine".