You have 1,000,000 number dice, on each of the dice one side measures one inch.

If you stack the dice on top of each other to make a huge tower, how tall could it reach? Explain your reasoning.
If you arrange the dice on the floor to make a square, could the square fit in the classroom? What would the dimensions be? Explain your reasoning.
If you layered the dice to make a giant cube, what would the dimensions of the cube be? Explain your reasoning.