A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 677160 can be evenly divided by 1 2 3 4 5 6 8 9 10 11 12 15 18 19 20 22 24 27 30 33 36 38 40 44 45 54 55 57 60 66 72 76 81 88 90 95 99 108 110 114 120 132 135 152 162 165 171 180 190 198 209 216 220 228 264 270 285 297 324 330 342 360 380 396 405 418 440 456 495 513 540 570 594 627 648 660 684 760 792 810 836 855 891 990 1,026 1,045 1,080 1,140 1,188 1,254 1,320 1,368 1,485 1,539 1,620 1,672 1,710 1,782 1,881 1,980 2,052 2,090 2,280 2,376 2,508 2,565 2,970 3,078 3,135 3,240 3,420 3,564 3,762 3,960 4,104 4,180 4,455 5,016 5,130 5,643 5,940 6,156 6,270 6,840 7,128 7,524 7,695 8,360 8,910 9,405 10,260 11,286 11,880 12,312 12,540 15,048 15,390 16,929 17,820 18,810 20,520 22,572 25,080 28,215 30,780 33,858 35,640 37,620 45,144 56,430 61,560 67,716 75,240 84,645 112,860 135,432 169,290 225,720 338,580 and 677,160, with no remainder.
Since 677,160 cannot be divided by just 1 and 677,160, it is not a prime number.