CDXLV is a Roman numeral that represents the number 445. In this numeral system, "C" stands for 100, "D" for 500, "X" for 10, "L" for 50, and "V" for 5. The combination of these letters indicates that you subtract 100 from 500 (D - C) and then add 50 (L) and 5 (V) to arrive at 445. Roman numerals, like CDXLV, were widely used in ancient Rome for various purposes, including numbering pages, clock faces, and denoting years. This numeral system is still used today in specific contexts, such as in the titles of movies and books or to indicate the year of production.