• 198 can be written using four 4's:
198 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.
198 is an esthetic number in base 13, because in such base its adjacent digits differ by 1.
198 is strictly pandigital in base 4.
It is a Curzon number.
It is a plaindrome in base 12 and base 13.
It is a nialpdrome in base 3, base 6, base 15 and base 16.
It is a self number, because there is not a number n which added to its sum of digits gives 198.
It is a congruent number.
198 is a gapful number since it is divisible by the number (18) formed by its first and last digit.
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
198 is a wasteful number, since it uses less digits than its factorization.
198 is an evil number, because the sum of its binary digits is even.
The square root of 198 is about 14.0712472795. The cubic root of 198 is about 5.8284766833.
Adding to 198 its sum of digits (18), we get a cube (216 = 63).
198 divided by its sum of digits (18) gives a palindrome (11).
Adding to 198 its reverse (891), we get a square (1089 = 332).
The spelling of 198 in words is "one hundred ninety-eight", and thus it is an aban number.