What is the number which is listed as the first ingredient on some bottles? September 21, 2020 19:36 This is a formula number, allowing us to more easily identify which bottle contains which formula. Related articles Can I mix my AlumierMD sunscreen with makeup or other skincare products before applying it to my face? What clinical testing was performed on AlumierMD products? What’s the difference between AlumierMD products and products sold at drugstores? What is “angel dusting”? Are the products vegan friendly?