1021
(1000000000000000000000; 10007; short scale: one sextillion; long scale: one thousand trillion, or one trilliard)
ISO: zetta- (Z)
- Geo — Grains of sand: All the world's beaches combined have been estimated to hold roughly 1021 grains of sand.
- Mathematics — Sudoku: There are 6,670,903,752,021,072,936,960 (≈6.7×1021) 9×9 sudoku grids.
- Astronomy — Stars: 70 sextillion = 7×1022, the estimated number of stars within range of telescopes (as of 2003); see mass of the observable universe.
- Mathematics: 146,361,946,186,458,562,560,000 (≈1.5×1023) is the fifth unitary perfect number.
Read more about this topic: Orders Of Magnitude (numbers)