How long would it take for the entire population of the USA to solve all possible unique 9x9 normal Sudoku grids, with no repetition of any grid?

The 9x9 Sudoku boards have approximately 6.670903752×10²¹ unique solutions. This number is exceedingly large and indicates the vast number of different combinations that exist in a Sudoku board of this size. The value was estimated through computations based on computational capacities and algorithms, but it's important to note that this is an estimation. Determining its exact value would require complex computational methods.

The population of the United States is constantly changing. According to the latest data, the population of the United States ranges between approximately 330 and 335 million people. The population of the USA is diverse and resides across various regions of the country. However, it's worth noting that these figures can fluctuate due to demographic changes, migration, and other factors. For the most up-to-date information, it's advisable to refer to official statistical sources or recent demographic data.

If one person solves a Sudoku puzzle in 4 minutes, solving all puzzles would take 6.670903752×10²¹x 4minutes = 2.66836x10²² minutes. Considering the entire population of the USA, which is around 332,000,000 people, it would take 2.66836x10²² / 332.000.000 = 8.03723x10¹³ minutes to solve all variations simultaneously. Translated into years based on a 365-day calendar, this amounts to 8.03723x10¹³ / (60x24x365) = 152915400.2 years.

In summary, if the entire population of the USA were to continuously solve Sudoku puzzles, it would take 153 million years approximately to solve all the possible 9x9 Sudoku boards.