A unique 24-bit number assigned by the wireless service provider (carrier) to each phone it sells or includes in service plans.
Unlike an Electronic Serial Number (ESN), a MIN is changeable because wireless phones may change hands or phone owners may move to another coverage region, requiring a different service plan.
The MIN and ESN are both automatically transmitted to the wireless network each time the phone is used to verify that the phone has not been reported lost or stolen and that all subscriber bills are current.