18993 has 8 divisors (see below), whose sum is σ = 27328. Its totient is φ = 11664.

The previous prime is 18979. The next prime is 19001. The reversal of 18993 is 39981.

It is a happy number.

18993 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

18993 is an esthetic number in base 12, because in such base its adjacent digits differ by 1.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18993 - 2⁹ = 18481 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a nialpdrome in base 13.

It is a self number, because there is not a number n which added to its sum of digits gives 18993.

It is not an unprimeable number, because it can be changed into a prime (18913) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 205 + ... + 282.

It is an arithmetic number, because the mean of its divisors is an integer number (3416).

2¹⁸⁹⁹³ is an apocalyptic number.

18993 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

18993 is a deficient number, since it is larger than the sum of its proper divisors (8335).

18993 is a wasteful number, since it uses less digits than its factorization.

18993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 503.

The product of its digits is 1944, while the sum is 30.

The square root of 18993 is about 137.8150935130. The cubic root of 18993 is about 26.6807391002.

It can be divided in two parts, 189 and 93, that added together give a palindrome (282).

The spelling of 18993 in words is "eighteen thousand, nine hundred ninety-three".