Seventeen is prime, and Plutarch preserves the report that the Pythagoreans disliked it, because it falls between sixteen and eighteen and so, in their musical arithmetic, breaks the neat ratio the two even numbers make around it. In Italy seventeen, not thirteen, is the unlucky number: the Roman numeral XVII can be rearranged into VIXI, Latin for I have lived, and so read as a memento of death, which is why some Italian buildings and airlines skip the seventeenth. Plutarch also places the death of Osiris on the seventeenth of the month Athyr, tying the number to the beginning of the god's dismemberment. These are scattered rather than systematic associations, but they share an undertone of unease that is unusual for a small number.
Cheiro's 1926 Book of Numbers gives seventeen a reading that sits closer to the Italian unease already described than to Islam's positive use of it: his compound-number scheme names seventeen the Star, read as hope glimpsed but not yet reached, an unusually apt pairing with the wary, not-quite-arrived character the number carries in the Mediterranean tradition, though Cheiro's own reading is a twentieth-century construction and no evidence ties it to the older Roman unease over the anagram VIXI.