You can freeze the sweet potatoes even when raw and whole but just be aware that if you do freeze the sweet potatoes that they may be mushy and soggy when you thaw them out.
It's best to cut up the sweet potatoes and then blanch the sweet potatoes first and then freeze them in bags.
When you blanch the sweet potatoes before freezing them it prevents the sweet potatoes from becoming soggy and wet and mushy when you thaw them out.
Or you can bake the sweet potatoes then freeze them that way as well and they will be okay for up to 6 months in the freezer.
It's best to eat the sweet potatoes within 6 months of freezing them but they will remain safe for up to a year in the freezer.