A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 910980 can be evenly divided by 1 2 3 4 5 6 7 9 10 12 14 15 18 20 21 27 28 30 35 36 42 45 54 60 63 70 84 90 105 108 126 135 140 180 189 210 241 252 270 315 378 420 482 540 630 723 756 945 964 1,205 1,260 1,446 1,687 1,890 2,169 2,410 2,892 3,374 3,615 3,780 4,338 4,820 5,061 6,507 6,748 7,230 8,435 8,676 10,122 10,845 13,014 14,460 15,183 16,870 20,244 21,690 25,305 26,028 30,366 32,535 33,740 43,380 45,549 50,610 60,732 65,070 75,915 91,098 101,220 130,140 151,830 182,196 227,745 303,660 455,490 and 910,980, with no remainder.
Since 910,980 cannot be divided by just 1 and 910,980, it is not a prime number.