One way of doing this is to use prime factorization.
2352 = 3 x 4 x 4 x 7 x 7
Looking at the above numbers, we see that if there was another 3 factor, it would be a perfect square.
So if our number was 3 x 3 x 4 x 4 x 7 x 7, it would be a perfect square.
That number multiplies out to be 7056. The square root of this number would be 3 x 4 x 7 = 84. Yay!