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