A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 4102920 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 15 18 20 24 27 29 30 36 40 45 54 58 60 72 87 90 108 116 120 131 135 145 174 180 216 232 261 262 270 290 348 360 393 435 522 524 540 580 655 696 783 786 870 1,044 1,048 1,080 1,160 1,179 1,305 1,310 1,566 1,572 1,740 1,965 2,088 2,358 2,610 2,620 3,132 3,144 3,480 3,537 3,799 3,915 3,930 4,716 5,220 5,240 5,895 6,264 7,074 7,598 7,830 7,860 9,432 10,440 11,397 11,790 14,148 15,196 15,660 15,720 17,685 18,995 22,794 23,580 28,296 30,392 31,320 34,191 35,370 37,990 45,588 47,160 56,985 68,382 70,740 75,980 91,176 102,573 113,970 136,764 141,480 151,960 170,955 205,146 227,940 273,528 341,910 410,292 455,880 512,865 683,820 820,584 1,025,730 1,367,640 2,051,460 and 4,102,920, with no remainder.
Since 4,102,920 cannot be divided by just 1 and 4,102,920, it is not a prime number.