LXXIII

LXXIII is the Roman numeral for the number 73. It is formed by the symbols L (50) plus XX (20) and III (3). Roman numerals are still used in various contexts to denote numbers, ordinals, years, chapters, and edition numbers.

In practice, LXXIII may appear to mark the 73rd item in a list or to indicate the year 73 CE or 73 BCE when dates are written in Roman numerals. It can also appear on monuments, in textual apparatus, or in the titles of works that employ Roman-numeral labeling. In modern writing, Arabic numerals are usually preferred for counting, with Roman numerals retained for stylistic or traditional purposes such as in certain clocks, outlines, or commemorative inscriptions.

In mathematics, 73 is a prime number, specifically the 21st prime. In base 2, 73 is represented as 1001001, which is a palindrome. These numeric properties are sometimes cited in recreational number theory, though they are independent of the Roman numeral representation LXXIII.

See also: Roman numerals, numeral systems, prime numbers.