That's right, March 14 is international Pi Day. Get it -- pi is 3.14, and March 14 is 3/14?

Most everyone knows pi -- the ratio of the circumference of a circle to its diameter. But how much do you really know about this magical number? Below are 28 fun facts about pi split up into tidy categories. Enjoy!

**[ MORE PI DAY:** 10 Awesome ways to celebrate Pi Day 2013

**EVEN MORE PI DAY:** 10 More ways to celebrate Pi Day

**FUN FACT:** How Indiana tried to redefine pi **]**

### Pi in society

Albert Einstein

-Pi Day is also Albert Einstein's birthday, along with the birthdays of Apollo 8 Commander Frank Borman, Astronomer Giovanni Schiaparelli, and last-man-on-the-moon Gene Cernan.

-There is a pi cologne.*

### Computing pi

-Computing pi is a stress test for a computer -- a kind of "digital cardiogram.*

-The record for calculating pi, as of 2010, is to 5 trillion digits (source: Gizmodo).

### Random pi information

- If you were to print 1 billion decimal values of pi in ordinary font it would stretch from New York City to Kansas (source: Buzzle).

- 3.14 backwards looks like PIE.

- "I prefer pi" is a palindrome.

### Pi jokes

-If you divide the circumference of the sun by its diameter, what will you have? Pi in the sky! (source: Jokes4us.com)

- What do you get if you divide the circumference of a jack-o'-lantern by its diameter? Pumpkin pi! (source: Jokes4us.com)

### Pi in movies and TV

-There's a reference to Pi in "Star Trek." Check it out here.*

-Many movies have been made about pi, including "Pi: Faith in Chaos," which is about a man who goes mad trying to rationalize pi.*

-Other movie references to pi include pi being the secret code in Alfred Hitchcock's "Tom Curtain" and "The Net" with Sandra Bullock.*

-In the book "Contact" by Carl Sagan, humans study pi to gain awareness about the universe.*

### Pi's numbers

-The first million decimal places of pi consist of 99,959 zeros, 99,758 ones, 100,026 twos, 100,229 threes, 100,230 fours, 100,359 fives, 99,548 sixes, 99,800 sevens, 99,985 eights and 100,106 nines.*

-There are no occurrences of the sequence 123456 in the first million digits of pi -- but of the eight 12345s that do occur, three are followed by another 5. The sequence 012345 occurs twice and, in both cases, it is followed by another 5.*

-The first six digits of pi (314159) appear in order at least six times among the first 10 million decimal places of pi.*

-At position 763 there are six nines in a row, which is known as the Feynman Point.^

### Pi the number

-The fraction 22/7 is a well-used number for Pi. It is accurate to 0.04025%.^

-Another fraction used as an approximation to Pi is (355/113), which is accurate to 0.00000849%.^

-A more accurate fraction of Pi is (104348/33215). This is accurate to 0.00000001056%.^

-The square root of 9.869604401 is approximately Pi.^

### The symbol pi

-In the Greek alphabet, pi (piwas) is the 16th letter. In the English alphabet, p is also the 16th letter.*

### There are pi haters

Tau Day

-Check out this slideshow of ways to celebrate Tau Day, an alternative calculation to Pi Day.

### Pi's evolution

-Around 2000 B.C., Babylonians established the constant circle ratio as 3 1/8 or 3.125. The ancient Egyptians arrived at a slightly different value of 3 1/7 or 3.143.*

-One of the earliest known records of pi was written by an Egyptian scribe named Ahmes (c. 1650 B.C.) on what is now known as the Rhind Papyrus. He was off by less than 1% of the modern approximation of pi (3.141592).*

-Plato (427-348 B.C.) supposedly obtained for his day a fairly accurate value for pi: √2 + √3 = 3.146.*

-The father of calculus (meaning "pebble used in counting," from calx or "limestone"), Isaac Newton, calculated pi to at least 16 decimal places.*

-William Jones (1675-1749) introduced the symbol "π" in the 1706, and it was later popularized by Leonhard Euler (1707-1783) in 1737.*

**Sources:**