It is a Curzon number.
It is a nialpdrome in base 14.
It is a congruent number.
1806 is an untouchable number, because it is not equal to the sum of proper divisors of any number.
21806 is an apocalyptic number.
It is a practical number, because each smaller number is the sum of distinct divisors of 1806, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2112).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
1806 is a wasteful number, since it uses less digits than its factorization.
1806 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 55.
The square root of 1806 is about 42.4970587218. The cubic root of 1806 is about 12.1779050055.
Adding to 1806 its reverse (6081), we get a palindrome (7887).
The spelling of 1806 in words is "one thousand, eight hundred six".