Question

For a given number, find the smallest whole number by which it should be divided so as to get a perfect square.

1620

Answer 1

$1620=2\times 2\times 5\times 3\times 3\times 3\times 3$

$1620=2^2\times 3^4\times 5$
1620 has an extra 5 as its factor for it to be a perfect square. Hence, it should be divided by 5 to get 324 which is a perfect square.
$\sqrt{324}=18$