A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 6883470 can be evenly divided by 1 2 3 5 6 9 10 11 15 17 18 22 30 33 34 45 51 55 66 85 90 99 102 110 153 165 170 187 198 255 306 330 374 409 495 510 561 765 818 935 990 1,122 1,227 1,530 1,683 1,870 2,045 2,454 2,805 3,366 3,681 4,090 4,499 5,610 6,135 6,953 7,362 8,415 8,998 12,270 13,497 13,906 16,830 18,405 20,859 22,495 26,994 34,765 36,810 40,491 41,718 44,990 62,577 67,485 69,530 76,483 80,982 104,295 125,154 134,970 152,966 202,455 208,590 229,449 312,885 382,415 404,910 458,898 625,770 688,347 764,830 1,147,245 1,376,694 2,294,490 3,441,735 and 6,883,470, with no remainder.
Since 6,883,470 cannot be divided by just 1 and 6,883,470, it is not a prime number.