"LXVI" is a Roman numeral that represents the number 66. Roman numerals are a numeral system originating from ancient Rome, using combinations of letters from the Latin alphabet. In this system, "L" stands for 50, "X" for 10, and "VI" for 6. Therefore, when combined, LXVI equals 66. Roman numerals are often used today in various contexts, such as in the naming of monarchs and popes, or to denote the chapters and verses in the Bible. They are also commonly seen on clock faces and in the titles of movies and events, providing a classic touch to modern usage.