Numbers are very significant, and different numbers have been important to many different cultures.
Three: to quote Multiplication Rock , "is a magic number". Christians especially revere it (Holy Trinity, Three Wise Men), but the Greeks did too (Three Fates, Three Graces, Three Furies) as well as the Norse (Three Norns), among others. Chinese numerology has 3 as a special number of luck.
Four: In North American native culture, four was the number of perfection, as in the seasons, and the elements (earth, air, fire, water).
Five: Natives thought five was instability, and brought bad luck.
Six: One less than perfection for Christians...the number of the beast's trinity (666).
Seven: Seven deadly sins, seven virtues. Perfection for Chirstians (the seven seals of Revelation). Also lucky in Chinese numbers, but I forget why...
Eight: The number of financial luck to Chinese. August 8, 1988 was the day that more Chinese weddings happened in Toronto than every other day that year! I don't know why I remember that...
Twelve: The number of apostles. That's why we have 12 on a jury.
Thirteen: Strictly a Christian superstition...it was the number of people at the Last Supper, and the thirteenth person is typically portrayed as being Judas Iscariot, the betrayer.
I looove numerology, but I don't know enough about it...yet!
But you are right n4h, as times change, numbers are given different symbology to different people...like 9/11. If you said 911 before 2001, you'd probably think "emergency, call the ambulance"...and that's not much different than what it means now, but with the added weight of planes hitting buildings...