8. It's the best number. It is a vertical infinity sign. If you were born on an eighth day you're amazing. If you're a libra too you're Jesus riding a unicorn.
When i met my wife I kept seeing the numbers 111 and 333. Looked it up and they're supposedly lucky or divine or something. I think it's nonsense, but it stuck out enough to be annoying.
21. I don't know why, it just seems to be everywhere around me. Everytime i have to choose a number for some reason, i go for 21. It never disappointed me, as far as i remember.
Luck is success brought by chance, instead of actions. The chance is random. Therefore, you can't have a lucky number, you just think you have one, because setting one contradicts its randomness.