What is the difference among the application number, publication number, and patent number? I just know that application number is a 8-digit number, and the publication number is 11-digit while the patent number is 7-digit. However, it confused me when we will get a application number? a publication number? a patent number?
I assume you are talking about the US for the formats.
The application number is assigned when the application is filed at the USPTO. It is of the format "16/123456".
The publication number is assigned when the application is published (usually 18 months after it was filed). It is of the format "2016/0123456".
The patent number is assigned if the application is granted. It is of the format "9123456".