Find the least number by which 243 must be divided to make it a perfect

square.

Is 243 a perfect square number? A number is a perfect square (or a square number) if its square root is an integer; that is to say, it is the product of an integer with itself. Here, the square root of 243 is about 15.588. Thus, the square root of 243 is not an integer, and therefore 243 is not a square number.