• 189 can be written using four 4's:
189 is nontrivially palindromic in base 2.
It is an Ulam number.
It is an alternating number because its digits alternate between odd and even.
It is a Duffinian number.
It is a Curzon number.
189 is a lucky number.
It is a plaindrome in base 5, base 10, base 12, base 13 and base 16.
It is a nialpdrome in base 3, base 14 and base 15.
It is a congruent number.
189 is the 9-th heptagonal number.
It is an amenable number.
189 is an equidigital number, since it uses as much as digits as its factorization.
189 is an evil number, because the sum of its binary digits is even.
The square root of 189 is about 13.7477270849. The cubic root of 189 is about 5.7387935483.
Subtracting from 189 its sum of digits (18), we obtain a palindrome (171).
The spelling of 189 in words is "one hundred eighty-nine", and thus it is an aban number.