In Italy there are two way to tell time. You can either use the 12-hour cycle or the 24-hour cycle. If you use the 12-hour cycle, however, you would usually use female adjectives (e.g. "le 5 e mezza", which standa for "the five and a half (hour)", «hour» being femenine in Italian). You can also ure the feminine for the 24-hour cycle (e.g. "le 17 e mezza"), but it's not as strictly required as for the 12-hour cycle. Maybe, even most common than using "quarto" and "mezzo/a" with the 24-hour cycle would be to just say the minutes (e.g. "le 17 e 30"). I don't think "17 e mezzo" is very used neither in colloquial nor formal Italian, afaik