18311 has 2 divisors, whose sum is σ = 18312.
Its totient is φ = 18310.
The previous prime is 18307. The next prime is 18313. The reversal of 18311 is 11381.
18311 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.
It is a strong prime.
It is a cyclic number.
It is not a de Polignac number, because 18311 - 22 = 18307 is a prime.
Together with 18313, it forms a pair of twin primes.
It is a Chen prime.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (18313) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9155 + 9156.
It is an arithmetic number, because the mean of its divisors is an integer number (9156).
218311 is an apocalyptic number.
18311 is a deficient number, since it is larger than the sum of its proper divisors (1).
18311 is an equidigital number, since it uses as much as digits as its factorization.
18311 is an evil number, because the sum of its binary digits is even.
The product of its digits is 24, while the sum is 14.
The square root of 18311 is about 135.3181436467.
The cubic root of 18311 is about 26.3574882071.
Adding to 18311 its reverse (11381), we get a palindrome (29692).
The spelling of 18311 in words is "eighteen thousand, three hundred eleven".