A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 669600 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 15 16 18 20 24 25 27 30 31 32 36 40 45 48 50 54 60 62 72 75 80 90 93 96 100 108 120 124 135 144 150 155 160 180 186 200 216 225 240 248 270 279 288 300 310 360 372 400 432 450 465 480 496 540 558 600 620 675 720 744 775 800 837 864 900 930 992 1,080 1,116 1,200 1,240 1,350 1,395 1,440 1,488 1,550 1,674 1,800 1,860 2,160 2,232 2,325 2,400 2,480 2,700 2,790 2,976 3,100 3,348 3,600 3,720 4,185 4,320 4,464 4,650 4,960 5,400 5,580 6,200 6,696 6,975 7,200 7,440 8,370 8,928 9,300 10,800 11,160 12,400 13,392 13,950 14,880 16,740 18,600 20,925 21,600 22,320 24,800 26,784 27,900 33,480 37,200 41,850 44,640 55,800 66,960 74,400 83,700 111,600 133,920 167,400 223,200 334,800 and 669,600, with no remainder.
Since 669,600 cannot be divided by just 1 and 669,600, it is not a prime number.