Sudoku Combinations: How Many Possible Sudoku Grids Exist?
Plus There are 6,670,903,752,021,072,936,960 possible ways to fill a 9×9 Sudoku grid legally — roughly 6.67 × 10²¹, or about 6.7 sextillion. That figure, computed in 2005 by mathematicians Bertram Felgenhauer…