Pi is the mathematical constant whose value is the ratio of any circle's circumference to its diameter.
circumference= pi * diameter.
It is a mathematically interesting number and it is a known irrational number (a number which cannot be expressed as a fraction).
If there is any sacredness of this number, it won't be the approximation 22/7. However if you are interested in that kind of BS, a Patrick Mulcahy has written a small book "the Metaphyical Significance of Pi".
I hope this post can save you some time in case you are interested in Pi.
BTW, you can get pi to 1 million places here, a billion decimal places here.
If you like to have pi to 100 billion digits, click here.
Now, that's interesting.