A lucky number in the cultural sense is one that's traditionally considered auspicious — bringing good fortune, prosperity, or favor — in at least one major world culture. Different cultures favor different numbers:
- Chinese: 6 ("smooth"), 8 ("prosperity"), 9 ("long-lasting"). Triple combinations (888, 999) are especially favored.
- Western: 7 (recurring in religion and folklore — seven seas, seven wonders, seven days).
- Japanese: 7 (Seven Lucky Gods) and 8.
- Jewish: 18 (חי "chai" / "life"), 36 (twice chai).
- Italian: 13 (the opposite of the Western unlucky reading).
Not every culture's beliefs overlap — 13 is unlucky in most of the West but lucky in Italy; 9 is lucky in China but unlucky in Japan. The tag fires when any culture in our table marks the number lucky.