Yes apples can be frozen whole.
To freeze whole apples place the whole apples on a cookie sheet first and then freeze them until frozen.
Then once the apples are frozen on the cookie sheet you can remove them and place them in a freezer bag or in a freezer safe container.
Slicing apples first before freezing them is much better when you freeze apples but you can freeze apples whole if you want too.
I've frozen whole apples using the above method many times and they came out just as fresh as before.
I mostly keep frozen apples for baking pies and other cooking for later so they don't have to be as fresh as when freshly picked or freshly bought.