A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 7547540 can be evenly divided by 1 2 4 5 7 10 11 13 14 20 22 26 28 29 35 44 52 55 58 65 70 77 91 110 116 130 140 143 145 154 169 182 203 220 260 286 290 308 319 338 364 377 385 406 455 572 580 638 676 715 754 770 812 845 910 1,001 1,015 1,183 1,276 1,430 1,508 1,540 1,595 1,690 1,820 1,859 1,885 2,002 2,030 2,233 2,366 2,639 2,860 3,190 3,380 3,718 3,770 4,004 4,060 4,147 4,466 4,732 4,901 5,005 5,278 5,915 6,380 7,436 7,540 8,294 8,932 9,295 9,802 10,010 10,556 11,165 11,830 13,013 13,195 16,588 18,590 19,604 20,020 20,735 22,330 23,660 24,505 26,026 26,390 29,029 34,307 37,180 41,470 44,660 49,010 52,052 52,780 53,911 58,058 65,065 68,614 82,940 98,020 107,822 116,116 130,130 137,228 145,145 171,535 215,644 260,260 269,555 290,290 343,070 377,377 539,110 580,580 686,140 754,754 1,078,220 1,509,508 1,886,885 3,773,770 and 7,547,540, with no remainder.
Since 7,547,540 cannot be divided by just 1 and 7,547,540, it is not a prime number.