The least perfect square which is divisible by each of 21, 36 and 66 is = ?

Explanation:-

L.C.M. of (21, 36, 66)
= 21 × 12 × 11
= 7 × 3 × 4 × 3 × 11
= 7 × 3 × 2 × 2 × 3 × 11
For perfect square multiply by 7 × 11
So that pairs of number from perfect square
∴ 7 × 7 × 3 × 3 × 2 × 2 × 11 × 11
Required result is
= 213444 (which is a perfect square)