A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 8811780 can be evenly divided by 1 2 3 4 5 6 10 12 15 17 20 30 34 51 53 60 68 85 102 106 159 163 170 204 212 255 265 318 326 340 489 510 530 636 652 795 815 901 978 1,020 1,060 1,590 1,630 1,802 1,956 2,445 2,703 2,771 3,180 3,260 3,604 4,505 4,890 5,406 5,542 8,313 8,639 9,010 9,780 10,812 11,084 13,515 13,855 16,626 17,278 18,020 25,917 27,030 27,710 33,252 34,556 41,565 43,195 51,834 54,060 55,420 83,130 86,390 103,668 129,585 146,863 166,260 172,780 259,170 293,726 440,589 518,340 587,452 734,315 881,178 1,468,630 1,762,356 2,202,945 2,937,260 4,405,890 and 8,811,780, with no remainder.
Since 8,811,780 cannot be divided by just 1 and 8,811,780, it is not a prime number.