A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 8672670 can be evenly divided by 1 2 3 5 6 9 10 15 18 27 30 43 45 54 81 83 86 90 129 135 162 166 215 243 249 258 270 387 405 415 430 486 498 645 747 774 810 830 1,161 1,215 1,245 1,290 1,494 1,935 2,241 2,322 2,430 2,490 3,483 3,569 3,735 3,870 4,482 5,805 6,723 6,966 7,138 7,470 10,449 10,707 11,205 11,610 13,446 17,415 17,845 20,169 20,898 21,414 22,410 32,121 33,615 34,830 35,690 40,338 52,245 53,535 64,242 67,230 96,363 100,845 104,490 107,070 160,605 192,726 201,690 289,089 321,210 481,815 578,178 867,267 963,630 1,445,445 1,734,534 2,890,890 4,336,335 and 8,672,670, with no remainder.
Since 8,672,670 cannot be divided by just 1 and 8,672,670, it is not a prime number.