A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3670240 can be evenly divided by 1 2 4 5 7 8 10 14 16 20 28 29 32 35 40 56 58 70 80 112 113 116 140 145 160 203 224 226 232 280 290 406 452 464 560 565 580 791 812 904 928 1,015 1,120 1,130 1,160 1,582 1,624 1,808 2,030 2,260 2,320 3,164 3,248 3,277 3,616 3,955 4,060 4,520 4,640 6,328 6,496 6,554 7,910 8,120 9,040 12,656 13,108 15,820 16,240 16,385 18,080 22,939 25,312 26,216 31,640 32,480 32,770 45,878 52,432 63,280 65,540 91,756 104,864 114,695 126,560 131,080 183,512 229,390 262,160 367,024 458,780 524,320 734,048 917,560 1,835,120 and 3,670,240, with no remainder.
Since 3,670,240 cannot be divided by just 1 and 3,670,240, it is not a prime number.