A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2125980 can be evenly divided by 1 2 3 4 5 6 9 10 12 15 18 20 27 30 31 36 45 54 60 62 90 93 108 124 127 135 155 180 186 254 270 279 310 372 381 465 508 540 558 620 635 762 837 930 1,116 1,143 1,270 1,395 1,524 1,674 1,860 1,905 2,286 2,540 2,790 3,348 3,429 3,810 3,937 4,185 4,572 5,580 5,715 6,858 7,620 7,874 8,370 11,430 11,811 13,716 15,748 16,740 17,145 19,685 22,860 23,622 34,290 35,433 39,370 47,244 59,055 68,580 70,866 78,740 106,299 118,110 141,732 177,165 212,598 236,220 354,330 425,196 531,495 708,660 1,062,990 and 2,125,980, with no remainder.
Since 2,125,980 cannot be divided by just 1 and 2,125,980, it is not a prime number.