A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1370460 can be evenly divided by 1 2 3 4 5 6 7 10 12 13 14 15 20 21 26 28 30 35 39 42 52 60 65 70 78 84 91 105 130 140 156 182 195 210 251 260 273 364 390 420 455 502 546 753 780 910 1,004 1,092 1,255 1,365 1,506 1,757 1,820 2,510 2,730 3,012 3,263 3,514 3,765 5,020 5,271 5,460 6,526 7,028 7,530 8,785 9,789 10,542 13,052 15,060 16,315 17,570 19,578 21,084 22,841 26,355 32,630 35,140 39,156 45,682 48,945 52,710 65,260 68,523 91,364 97,890 105,420 114,205 137,046 195,780 228,410 274,092 342,615 456,820 685,230 and 1,370,460, with no remainder.
Since 1,370,460 cannot be divided by just 1 and 1,370,460, it is not a prime number.