A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1982460 can be evenly divided by 1 2 3 4 5 6 10 12 15 19 20 30 37 38 47 57 60 74 76 94 95 111 114 141 148 185 188 190 222 228 235 282 285 370 380 444 470 555 564 570 703 705 740 893 940 1,110 1,140 1,406 1,410 1,739 1,786 2,109 2,220 2,679 2,812 2,820 3,478 3,515 3,572 4,218 4,465 5,217 5,358 6,956 7,030 8,436 8,695 8,930 10,434 10,545 10,716 13,395 14,060 17,390 17,860 20,868 21,090 26,085 26,790 33,041 34,780 42,180 52,170 53,580 66,082 99,123 104,340 132,164 165,205 198,246 330,410 396,492 495,615 660,820 991,230 and 1,982,460, with no remainder.
Since 1,982,460 cannot be divided by just 1 and 1,982,460, it is not a prime number.