In brief
The sweet potato can be baked whole or cooked in a microwave oven. Softness is a more useful criterion than blindly following minutes.
Useful to know
For baking, choose a sweet potato that is firm and has no cracks, soft spots or sprouts. Wash it under running water and use a brush for the surface. [1]
In the example of the University of Iowa, the entire sweet potato is spiked and baked at 400°F, approximately 204°C, until softened. The range indicated is 45 minutes to an hour. It is an indication of a specific method of preparation, not a promise of each size and each oven. [1]
If you are preparing several servings, select close-sized potatoes or check each one individually. After softening, you can use the inside as a mash or serve the potato sliced. You don't have to change the size and the temperature and the method at the same time when you make the first attempt.
When stored, the healthy whole product and the already cooked portion have different conditions. Do not automatically carry the directions for raw sweet potato on the finished food.
Sources
For further detail and to check the information: