CXXI is the Roman numeral representation for the number 121. Roman numerals are a numeral system originating from ancient Rome, using combinations of letters from the Latin alphabet. In this system, "C" stands for 100, "X" for 10, and "I" for 1. Therefore, CXXI is calculated as 100 + 10 + 10 + 1, which equals 121. The number 121 is a perfect square, as it is the result of multiplying 11 by itself (11 x 11). It is also an odd number and can be found in various mathematical contexts, such as in geometry and number theory. Additionally, 121 is significant in science and history, appearing in various measurements and events.