The number π (spelled out as "pi") is a mathematical constant
that is the ratio of a circle's circumference to its diameter,
approximately equal to 3.14159. (reference)
Here are the first 53 digits of pi.
3 . 1 4 1 5
9 2 6 5 3 5
8 9 7 9 3 2
3 8 4 6 2 6
4 3 3 8 3 2
7 9 5 0 2 8
8 4 1 9 7 1
6 9 3 9 9 3
7 5 1 0 5 8
Here is a light-hearted version of the story of pi in a 4
minute video.
Here is a serious version of the story of pi in a long
text.
1,000
decimal places of pi
10,000
decimal places of pi
100,000
decimal places of pi
1,000,000
decimal places of pi
(reference)