A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3522420 can be evenly divided by 1 2 3 4 5 6 9 10 11 12 15 18 20 22 27 30 33 36 44 45 54 55 60 66 90 99 108 110 132 135 165 180 198 220 270 297 330 396 495 540 593 594 660 990 1,186 1,188 1,485 1,779 1,980 2,372 2,965 2,970 3,558 5,337 5,930 5,940 6,523 7,116 8,895 10,674 11,860 13,046 16,011 17,790 19,569 21,348 26,092 26,685 32,022 32,615 35,580 39,138 53,370 58,707 64,044 65,230 78,276 80,055 97,845 106,740 117,414 130,460 160,110 176,121 195,690 234,828 293,535 320,220 352,242 391,380 587,070 704,484 880,605 1,174,140 1,761,210 and 3,522,420, with no remainder.
Since 3,522,420 cannot be divided by just 1 and 3,522,420, it is not a prime number.