XVII

XVII is the Roman numeral designation for the number 17. It is formed by combining X (10) + V (5) + I (1) + I (1), with the numerals written in descending order.

In usage, XVII appears in contexts that employ Roman numerals, such as year designations, chapter or volume numbering, and regnal or dynastic enumerations. It is common in historical inscriptions and texts to see centuries written in Roman form (for example, the XVIIth century) or dynasties labeled with Roman numerals (such as the XVII Dynasty in Egypt). The form is also used in modern settings for stylized labeling, film or literature titles, and classical-themed material.

In mathematics, 17 is notable as a prime number, the seventh prime overall. It is one of the Fermat primes, of the form 2^(2^n) + 1 (specifically for n = 0, 1, 2, 3, 4 yielding 3, 5, 17, 257, 65537). As a prime not divisible by any smaller integer, 17 is also expressible as a sum of two squares: 17 = 1^2 + 4^2, reflecting a property common to primes congruent to 1 modulo 4.

Numerous cultural and scientific references use XVII to denote the number 17, reinforcing its identity across disciplines. Beyond its numeric value, XVII serves as a compact symbolic label in contexts ranging from historical dating to mathematical classification.