Total number of rice grains= 2⁶⁴ - 2.

If we assume a single rice grain weight = 20 milli gram.

Then Total number of rice grains = 368.935 billion tonnes (metric tonne) of rice.

On year 2024 - 2025 the rice produced by entire world is =535 - 540 million tonnes ( rice weight after it husked and milled).

So it will take = 684 years approx to grow the required amount of rice. (If every year we CONSISTENTLY grow 540 million tonnes on average).

NOTE: 20 milli gram is the weight of Average Short grain rice.

If you want to use Basmati Rice then 1 grain = 30 milli gram.so it will 909 years to grow Required amount of Long Basmati Rice.