There was seven of them in their space program.
7 = Swans a-swimming
7 Sides on a heptagon
7 colours in the spectrum
7 Sides on a Twenty Pence Coin
it means 7stah
1 7 star hotel in the world
7 Sides on a Twenty Pence Coin
snow white seven dwarfs
7 Dwarfs in Snow White (Story)
7 Digits in a Zip Code
7980 crowns, fees included.
If you mean the greatest prime factor of 210 it is 7.