1 and 1~2 digits: codes representing provinces.

2. 3rd-4th digits: codes representing prefecture-level cities.

3. 5th to 6th digits: codes representing districts and counties.

4. The number 7~ 14: indicates the date of birth, where the numbers 7, 8, 9 and 10 are years, the numbers 1 1 2 are months, and the numbers 13 and/kloc.

5. The number 15~ 17 is the serial code of people born in the same address jurisdiction and on the same day of the same year. At the same time, the number 17 has the function of gender recognition, with odd numbers for men and even numbers for women.

6. Number 18: It is a check code, which can be a number from 0 to 9, and is sometimes represented by X. It is calculated from the first 17 bits according to a complex formula, and is used to check the correctness of the ID number. When entering the ID number, please ensure that each digit is accurate, otherwise the real-name authentication may fail.