The account number is nine digits. The household registration number is randomly generated by the household registration management system of the public security organ. It is the number of the household registration management of the Public Security Bureau, with nine digits, which has no external effect and is convenient for internal management to find the original files. The account number is usually used to go through the relevant formalities in the place where the account is located, which is convenient for the relevant departments to manage, query and call the population information.