18013 has 2 divisors, whose sum is σ = 18014.
Its totient is φ = 18012.
The previous prime is 17989. The next prime is 18041. The reversal of 18013 is 31081.
Adding to 18013 its reverse (31081), we get a palindrome (49094).
18013 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 17689 + 324 = 133^2 + 18^2
It is an emirp because it is prime and its reverse (31081) is a distict prime.
It is a cyclic number.
It is not a de Polignac number, because 18013 - 25 = 17981 is a prime.
It is equal to p2065 and since 18013 and 2065 have the same sum of digits, it is a Honaker prime.
It is a nialpdrome in base 12.
It is a junction number, because it is equal to n+sod(n) for n = 17984 and 18002.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (18043) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9006 + 9007.
It is an arithmetic number, because the mean of its divisors is an integer number (9007).
218013 is an apocalyptic number.
It is an amenable number.
18013 is a deficient number, since it is larger than the sum of its proper divisors (1).
18013 is an equidigital number, since it uses as much as digits as its factorization.
18013 is an evil number, because the sum of its binary digits is even.
The product of its (nonzero) digits is 24, while the sum is 13.
The square root of 18013 is about 134.2125180451.
The cubic root of 18013 is about 26.2137216161.
The spelling of 18013 in words is "eighteen thousand, thirteen".