A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1137780 can be evenly divided by 1 2 3 4 5 6 7 9 10 12 14 15 18 20 21 27 28 30 35 36 42 43 45 49 54 60 63 70 84 86 90 98 105 108 126 129 135 140 147 172 180 189 196 210 215 245 252 258 270 294 301 315 378 387 420 430 441 490 516 540 588 602 630 645 735 756 774 860 882 903 945 980 1,161 1,204 1,260 1,290 1,323 1,470 1,505 1,548 1,764 1,806 1,890 1,935 2,107 2,205 2,322 2,580 2,646 2,709 2,940 3,010 3,612 3,780 3,870 4,214 4,410 4,515 4,644 5,292 5,418 5,805 6,020 6,321 6,615 7,740 8,127 8,428 8,820 9,030 10,535 10,836 11,610 12,642 13,230 13,545 16,254 18,060 18,963 21,070 23,220 25,284 26,460 27,090 31,605 32,508 37,926 40,635 42,140 54,180 56,889 63,210 75,852 81,270 94,815 113,778 126,420 162,540 189,630 227,556 284,445 379,260 568,890 and 1,137,780, with no remainder.
Since 1,137,780 cannot be divided by just 1 and 1,137,780, it is not a prime number.