ABSTRACT
We may never know the answer to the title question. Although there
are some efficient algorithms for computing pi, they all require comput-
ing the decimal digits sequentially, 3.14159 etc., and even with the most
powerful computers available, it would simply take too long to reach the
quadrillionth place. A quadrillion is 1015. At the time of writing, pi has
been computed to just over 1.25 trillion decimal places. For the record, the
ten decimal places ending in position one trillion are 6680122702. We’ll
come back later (in Chapter 7) to efforts to determine ever more of the dec-
imal expansion of pi and describe some of the methods used, but for now
we want to look at a slightly different question: what is the quadrillionth
place in the binary expansion of pi?
