Trivia worth memorizing

Fun Facts About Pi

Pi has been surprising mathematicians for more than 4,000 years. Here are the best weird-but-true facts about the number that refuses to end.

The record-breaking facts

As of 2024, pi has been computed to 202 trillion digits — which would take you about 6.4 million years to read out loud at one digit per second.
The current Guinness record for memorizing pi is 70,030 digits, held by Suresh Kumar Sharma of India (2015), who took 17 hours to recite them.
Akira Haraguchi of Japan claims an unofficial record of 100,000 digits, recited over 16 hours in 2006.
In 2022, Google engineer Emma Haruka Iwao computed pi to 100 trillion digits in 157 days.

At position 762 of pi, six nines appear in a row (999999). This is called the Feynman point because physicist Richard Feynman once said he'd like to memorize pi up to that spot so he could recite it as "…nine nine nine nine nine nine, and so on."
The first occurrence of 0123456789 in pi's decimal expansion is at position 17,387,594,880 — about 17 billion digits in.
The digits of pi pass every statistical test for randomness, but no-one has ever proven pi is "normal" (meaning every finite sequence appears with its expected frequency).

Ludolph van Ceulen spent most of his life computing pi to 35 digits. When he died in 1610, the digits were engraved on his tombstone in Leiden.
The letter π was first used for this ratio in 1706 by Welsh mathematician William Jones. Before that, it was written out as "the quantity which, when the diameter is multiplied by it, yields the circumference."
In 1897, the Indiana state legislature almost passed a bill that would have legally redefined pi as 3.2, based on a misguided "proof" by an amateur mathematician. A visiting math professor intervened and killed the bill.

Buffon's needle: Drop a needle on a lined floor. The probability it crosses a line gives you π — without measuring a single circle.
The Basel problem: Add up 1 + 1/4 + 1/9 + 1/16 + … (reciprocals of squares). The sum is exactly π²/6.
Euler's identity: e^(iπ) + 1 = 0. A single equation tying together five of the most important numbers in mathematics: 0, 1, e, i, and π.
You need only 39 digits of pi to compute the circumference of the observable universe to the width of a hydrogen atom.

NASA's JPL uses only 15 digits of pi for interplanetary navigation. Anything more is unnecessary precision.
Every Pi Day (March 14), bakeries around the world hold "buy a pie" promotions at 3:14 PM, and universities host pi-recitation contests.
Albert Einstein was born on March 14, which is a coincidence so perfect that Pi Day doubles as Einstein Day.
Stephen Hawking died on Pi Day 2018, also a coincidence, but one that felt meaningful.