Just started to renovate my mother's kitchen and already got some of the appliances to install but I realized there's a 3-prong dryer outlet instead of a stove outlet when I removed the counter top stove. Should I call an electrician to get it replaced or is there an adapter I could use for it?
We'll be looking a lot at the NEMA connector page for these, since they're the controlling entity for the outlet and plug sizes, shapes, and performance (volt/amp).
Now, what you're referring to as a "dryer outlet" is presumably the (now-deprecated) NEMA 10 receptacle
These have been deprecated by the NEC (National Electical Code, assuming you live in the United States) due to the lack of a dedicated safety ground path.
The two lower prongs on the pictured plug each carry line voltage (240VAC measured phase-to-phase, 120VAC measured phase-to-ground), and the top prongs is the neutral conductor.
Traditionally, the frame of the dryer (in your case, the "counter top stove") was connected to the neutral conductor with a short wire jumper near where the neutral is wired into the plug on the back of the unit. This provided grounding for the frame of the appliance, because back at the breaker panel, the neutral conductor is connected to the safety ground, so the two terminals shared a conductor for that distance.
The reason this was changed is because of increasing safety regulations. The NEC requires now for appliances of this type to have a dedicated conductor for the safety ground from the breaker panel all the way to the appliance, instead of 'piggybacking' on the neutral conductor.
So for the grounding portion, it depends on what your "counter top stove" requires for the input power. Most electric clothes dryers have 240V heating elements, but a 120VAC motor, so they require the use of the neutral in that regard. If your stove only calls for 240VAC input (instead of 120VAC/240VAC), then you might be able to repurpose the old neutral wire for the dedicated ground wire. All of this is also dependent on the wire sizes and current-carrying capacities, as Billy C. pointed out.
All this being said, you'd be wise to involve someone qualified to verify wiring on the receptacle anyway, since it's an unconventional place to find a dryer outlet.
And more information (especially in the form of photos) is always helpful!