Routing numbers differ for checking and savings accounts, prepaid cards, IRAs, lines of credit, and wire transfers. Routing numbers are also known as banking routing numbers, routing transit numbers, RTNs, ABA numbers, and sometimes SWIFT codes (although these are quite different from routing numbers as SWIFT codes are solely used for international wire transfers while routing numbers are used for domestic transfers). A routing number is a 9 digit code for identifying a financial institute for the purpose of routing of checks (cheques), fund transfers, direct deposits, e-payments, online payments, etc.