The bank will receive a text message after withdrawing money, so is the mobile phone number that receives the text message the reserved number of the bank?

No, this is the mobile phone number of the account balance change SMS reminder service. The mobile phone number reserved by the bank refers to the mobile phone number left in the fast payment business of the bank, which has nothing to do with the non-overlapping business of the former. Two services can leave the same mobile phone number or two different mobile phone numbers.