In mathematics, at least four different functions are known as the pi or Pi function:

• ${\displaystyle \pi (x)\,\!}$ (pi function) – the prime-counting function
• ${\displaystyle \Pi (x)\,\!}$ (Pi function) – the gamma function when offset to coincide with the factorial
• Rectangular function
• ${\displaystyle \pi (n)\,\!}$ – the Pisano period

You might also be looking for:

• ${\displaystyle \prod _{n=1}^{\infty }}$ – the Infinite product of a sequence
• Capital pi notation

This disambiguation page lists articles associated with the title Pi function.
If an internal link led you here, you may wish to change the link to point directly to the intended article.