A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5396820 can be evenly divided by 1 2 3 4 5 6 10 11 12 13 15 17 20 22 26 30 33 34 37 39 44 51 52 55 60 65 66 68 74 78 85 102 110 111 130 132 143 148 156 165 170 185 187 195 204 220 221 222 255 260 286 330 340 370 374 390 407 429 442 444 481 510 555 561 572 629 660 663 715 740 748 780 814 858 884 935 962 1,020 1,105 1,110 1,122 1,221 1,258 1,326 1,430 1,443 1,628 1,716 1,870 1,887 1,924 2,035 2,145 2,210 2,220 2,244 2,405 2,431 2,442 2,516 2,652 2,805 2,860 2,886 3,145 3,315 3,740 3,774 4,070 4,290 4,420 4,810 4,862 4,884 5,291 5,610 5,772 6,105 6,290 6,630 6,919 7,215 7,293 7,548 8,140 8,177 8,580 9,435 9,620 9,724 10,582 11,220 12,155 12,210 12,580 13,260 13,838 14,430 14,586 15,873 16,354 18,870 20,757 21,164 24,310 24,420 24,531 26,455 27,676 28,860 29,172 31,746 32,708 34,595 36,465 37,740 40,885 41,514 48,620 49,062 52,910 63,492 69,190 72,930 79,365 81,770 83,028 89,947 98,124 103,785 105,820 122,655 138,380 145,860 158,730 163,540 179,894 207,570 245,310 269,841 317,460 359,788 415,140 449,735 490,620 539,682 899,470 1,079,364 1,349,205 1,798,940 2,698,410 and 5,396,820, with no remainder.
Since 5,396,820 cannot be divided by just 1 and 5,396,820, it is not a prime number.