CMXLVII

CMXLVII is the representation of the integer 947 in Roman numerals. Formed by combining the standard symbols CM (900), XL (40) and VII (7), it follows the subtractive notation rules of classical Roman numerals: CM denotes 1000 − 100, and XL denotes 50 − 10.

As a number, 947 is a three-digit positive integer and a prime number; its only positive divisors are 1 and 947. In common numeral systems it is written as 1110110011 in binary and 3B3 in hexadecimal. The sum of its decimal digits is 20. It is not a safe prime (since (947 − 1)/2 = 473 is composite) and it is not a Sophie Germain prime.

CMXLVII can appear in non-mathematical contexts where Roman numerals are used: enumerating chapters, volumes, event editions, clock faces, inscriptions, or marking years on monuments. In historical writing, the year 947 AD may be rendered as CMXLVII. The numeral adheres to conventional Roman-numeral ordering and subtraction rules and exemplifies the combination of both largest-to-smallest additive grouping with permitted subtractive pairs.