3686, written six-sixes-sur-demi-cent-sur-six-fois-six-cents (literally: six sixes over (½ x 100) over 6 x (6 x 100)) and pronounced /sis:sizəs:yr:dəmisãsyrsi.fwasis:ãs/, is a popular and culturally important number in the Republic of the Southern Indian Ocean Islands. As the last "unique" number in the Indian Ocean French number system, it is believed that the number represents luck and happiness, and can often be seen on culturally or personally important objects like buildings, boats, and gravestones.