# The H&FJ Institute for Unapplied Mathematics

April 22, 2009 8:27 AM Subscribe

Joe Palca, a science correspondent for NPR's Morning Edition, was meditating on the best way to convey the magnitude of the world's largest known prime number, 2

^{43112609}-1. He contacted H&FJ at Typography.com to discuss the implications of typesetting a number with more than twelve million digits. Crunching of numbers and fonts ensued.*Some have suggested that 13- and 17-year cicadas each follow prime numbered life cycles in order to ensure that their populations compete as little as possible, coexisting only once every 221 years.*

Wow. That is some swanky evolution right there.

Also, I just adore that this entire typographic discussion was for a piece

**on NPR.**

posted by CaptApollo at 8:46 AM on April 22, 2009

That number is written in invisible UV ink in very small print that wraps around the walls of my living room. Turn on the blacklight and it's a Prime Number Party!

posted by Burhanistan at 8:47 AM on April 22, 2009

posted by Burhanistan at 8:47 AM on April 22, 2009

*Also, I just adore that this entire typographic discussion was for a piece on NPR.*

You're probably not going to connect with many font nerds running a piece like this on Opie and Anthony's

*Whip 'em Out Wendesdays*.

posted by The Straightener at 8:57 AM on April 22, 2009 [2 favorites]

The fact that changing the kerning on the number pair "74" can cause a 150 ft variation in the length of the printed number is just amazing!

posted by djfiander at 8:57 AM on April 22, 2009

posted by djfiander at 8:57 AM on April 22, 2009

What about typesetting the hexadecimal representation? I'll start off:

FFFFFFFFFFFFFFFFFFFFFF......

posted by vacapinta at 9:12 AM on April 22, 2009 [14 favorites]

FFFFFFFFFFFFFFFFFFFFFF......

posted by vacapinta at 9:12 AM on April 22, 2009 [14 favorites]

the math gets quite a bit easier in fonts with tabular figures, where all of the digits are the same widthWhich, of course, is the only way one should ever actually typeset numbers in math or sciences. But, as they say, "but what fun is that?"

posted by Nelson at 9:27 AM on April 22, 2009

*Microsoft Excel can't even calculate any Mersenne prime with an exponent larger than 607.*

Well, if it confuses Excel, that's some bigass number indeed

posted by ElvisJesus at 10:03 AM on April 22, 2009

What's the largest prime number that is

posted by eye of newt at 10:34 AM on April 22, 2009

*not*a Mersenne Prime?posted by eye of newt at 10:34 AM on April 22, 2009

I found my own answer:

27653 × 2^9167433 + 1

(2,759,677 digits, much smaller than the Mersenne prime).

posted by eye of newt at 10:44 AM on April 22, 2009 [1 favorite]

27653 × 2^9167433 + 1

(2,759,677 digits, much smaller than the Mersenne prime).

posted by eye of newt at 10:44 AM on April 22, 2009 [1 favorite]

I remember Googling (OK, stalking) one of my computer science professors and discovered he was an avid GIMPS participant.

I don't have the stomach to sit on one number for two to three weeks, but I do participate in PrimeGrid, which is the next best thing. This prime number is my baby.

posted by spamguy at 11:32 AM on April 22, 2009

I don't have the stomach to sit on one number for two to three weeks, but I do participate in PrimeGrid, which is the next best thing. This prime number is my baby.

posted by spamguy at 11:32 AM on April 22, 2009

'bagatelle' is officially my word of the day.

posted by jimmythefish at 11:56 AM on April 22, 2009

posted by jimmythefish at 11:56 AM on April 22, 2009

And how long would it take the Prime Number Shitting Bear to get to this number?

posted by marxchivist at 12:48 PM on April 22, 2009 [4 favorites]

posted by marxchivist at 12:48 PM on April 22, 2009 [4 favorites]

20 miles, yeah, sure, but what's that in pica?

posted by klangklangston at 2:28 PM on April 22, 2009

posted by klangklangston at 2:28 PM on April 22, 2009

According to Google, 7,603,200. In postscript.20 miles, yeah, sure, but what's that in pica?

posted by scrump at 2:52 PM on April 22, 2009

So, I'm on PrimeGrid too. How often do they find a new prime number?

posted by reenum at 2:58 PM on April 22, 2009

posted by reenum at 2:58 PM on April 22, 2009

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posted by cavalier at 8:30 AM on April 22, 2009