The calculated distance (air line) between Millerovo and Rostov-na-Donu is approximately 121 miles respectively 195 kilometers.
By car or train, the actual journey to Rostov-na-Donu is certainly longer, as only the direct route (as the crow flies) between Millerovo and Rostov-na-Donu has been calculated here.
Air line (approximately)
195 kilometers
105 nautical miles