Answer
$1.845\times 10^{19}$ grains.
Work Step by Step
$a_{1}=1$
$a_{2}=1\cdot 2$
$a_{3}=1\cdot 2^{2}$
$a_{4}=1\cdot 2^{3}....$ a geometric sequence with
$a_{1}=1,\quad r=2,\quad n=64.$
The sum $S_{n}$ of the first $n$ terms is
$S_{n}=\displaystyle \sum_{k=1}^{n}a_{1}r^{k-1}=a_{1}\cdot\frac{1-r^{n}}{1-r}$
$S_{64}=1\displaystyle \frac{1-2^{64}}{1-2}=\frac{1-2^{64}}{-1}=2^{64}-1\approx 1.845\times 10^{19}$
$1.845\times 10^{19}$ grains.
Say that there are 10,000 grains in a kilogram,
there would be $10^{7}$ grains in a metric ton.
A semi trailer truck can haul say, 50 tons....
You would need about $3.69\times 10^{10} $semitrailer truckloads....
$36,900,000,000 $ trucks....
It is quite possible that this is more wheat than has ever been grown on earth.
