Primal Urge


Two to the power of Seventy-Four Million Two Hundred and Seven Thousand Two Hundred Eighty-One minus One, a Castor Design book series comprised of three volumes, transforms the largest prime number known into a physical object.

Did human beings discover mathematics, or did we invent it? Are concepts like perfect squares, parabolas and prime numbers real? Like, really real? Or are they just creations of the human mind?Arguably, math is a language, and therefore a human invention. But it’s a language unlike any other – its terms and concepts force themselves into the physical universe in a way that ordinary words do not.

Consider prime numbers. Nothing could feel more like a human construct. We are the ones who decided that numbers evenly divisible only by one and themselves were special. We named them and gave them their own category. We invented prime numbers. But primes are also, as Castor Design co-founder Brian Richer describes them, “an irrefutable truth.” Three, 13 and 2 74207281_ 1 would all be prime with or without our saying so.

Two to the power of Seventy-Four Million Two Hundred and Seven Thousand Two Hundred Eighty-One minus One, a Castor Design book series, makes the largest prime number known tangible.
Toronto studio Castor Design pushes M74207281, the largest prime number yet known, into the physical world as a limited-edition design object.

You may recognize that last term as the largest prime number currently known to humanity. Affectionately known as M74207281, it was discovered in January 2016 by a group of volunteers using distributed, collaborative computing. Richer has now transformed the number into a limited-edition, three-volume book containing all 22.3 million digits of M74207281.

Two to the power of Seventy-Four Million Two Hundred and Seven Thousand Two Hundred Eighty-One minus One, a Castor Design book series, makes the largest prime number known tangible.

Two to the power of Seventy-Four Million Two Hundred and Seven Thousand Two Hundred Eighty-One minus One transforms an inconceivably large number into a solid physical object. The book endows M74207281 with tangible properties like mass, volume, colour and shape. Each of the 3,982 Bible-paper pages displays about 5,600 numbers in Figgins Sans typeface. The black Bodoni title on the 18-by-27-centimetre cover stands out against a plain white background, and the set comes packed in a honed Carrara marble bookend. These quantifiable physical characteristics help put the “invented or discovered” debate to rest. Are mathematical concepts like M74207281 really real? It’s much easier to answer “yes” when you can prop open a window with one.


About Patchen Barss

Patchen Barss is a Toronto-based science journalist, speaker, and author.