How many cylinders for 3.6?

As many as the manufacturer decided to make it. Could be four, could be six, could be eight. Offhand, I can think of two engines of this displacement - the GM High Feature and the Chrysler Pentastar. Both are V6 engines. Some older European cars had V8 engines in a similar displacement range. The old Liberty aircraft engine was a V8 with 3.6 liter displacement, as is the Ford TDV8 diesel engine.

Displacement can provide a guideline as to the number of cylinders, but not a definitive answer. Class 8 heavy duty trucks (tractor-trailers, dump trucks, cement mixers, etc.) tend to have engines displacing anywhere from 10 to 16 liters, but will typically only have six cylinders, for example.