xxix

XXIX is the Roman numeral for the number 29. It is formed by the symbols X, X, and IX, where X represents 10 and IX represents 9; since IX is a subtractive combination, XXIX equals 10 + 10 + 9 = 29. In the system of Roman numerals, such numerals are commonly used for dates, chapter or volume numbering, and regnal numbers.

In mathematics, 29 is a prime number, specifically the tenth prime in the sequence of primes (2, 3, 5, 7, 11, 13, 17, 19, 23, 29). It is also a Sophie Germain prime, since 2×29 + 1 = 59 is prime. The number appears in various numerical contexts, including digit sums and modular arithmetic.

Culturally and historically, Roman numerals including XXIX are used in inscriptions, monuments, clock faces, and the stylized labeling of events, editions, or series where traditional typography is preferred. While XXIX itself does not denote a particular concept beyond the value 29, its form is widely recognized as part of the broader system of Roman numerals that continues to appear in modern labeling and design.

See also: Roman numerals, 29 (number), prime numbers, Sophie Germain prime.