XXXVII

XXXVII is the Roman numeral for the number 37. It is formed by XXX (30) and VII (7), and is used in contexts where Roman numerals appear, such as numbering chapters, monarchs, or regnal years, and in labeling calendar years, for example 37 CE or 37 BCE.

Mathematically, 37 is a prime number. It relates to the three-digit repunit factors: 37 × 3 = 111 and 37 × 27 = 999, which explains why 1/37 has a three-digit repeating cycle (0.027027…). A related property is that 10^3 ≡ 1 mod 37, reflecting its connection to the repeating pattern of multiples of 999.

Historically, the year 37 CE is notable for the accession of Caligula as Roman emperor, beginning his reign. The year 37 BCE is part of the late Roman Republic era, a period of significant political and military activity around the Mediterranean world.

In modern and popular usage, XXXVII may appear as a stylized designation for the 37th item in a sequence, edition number, or other enumerations where Roman numerals are employed for aesthetic or traditional reasons. See also Roman numerals for broader context on their formation and use.