The calculated distance (air line) between Šentilj v Slov. Goricah and Ptuj is approximately 21 miles respectively 34 kilometers.
By car or train, the actual journey to Ptuj is certainly longer, as only the direct route (as the crow flies) between Šentilj v Slov. Goricah and Ptuj has been calculated here.
Air line (approximately)
34 kilometers
18 nautical miles