A bank account number is a unique identifier assigned to an individual's or business's account at a financial institution. This number is used to facilitate transactions, such as deposits, withdrawals, and transfers, ensuring that funds are accurately directed to the correct account. Typically, a bank account number consists of a series of digits, which can vary in length depending on the bank and the country. It is important to keep this number confidential to prevent unauthorized access to the account and protect personal financial information.