The number $100$ has four perfect square divisors, namely $1,$ $4,$ $25,$ and $100.$ What is the smallest positive integer that has exactly $2$ perfect square divisors?
The number $100$ has four perfect square divisors, namely $1,$ $4,$ $25,$ and $100.$ What is the smallest positive integer that has exactly $2$ perfect square divisors?
That would be four ... it has two perfect square divisors, namely one and four.
+1518 
