Fun with numbers till 9999 !!!

 
Mathematical Genius- whoever did this, the first few are easy, he’s done it upto 9999 
Mind Blowing………………… 
0 s the additive identity.
1 is the multiplicative identity.
2 is the only even prime.
3 is the ! ! number of spatial dimensions we live in.
4 is the smallest number of colors sufficient to color all planar maps.
5 is the number [...]