A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2306772 can be evenly divided by 1 2 3 4 6 9 12 13 18 26 27 31 36 39 52 53 54 62 78 93 106 108 117 124 156 159 186 212 234 279 318 351 372 403 468 477 558 636 689 702 806 837 954 1,116 1,209 1,378 1,404 1,431 1,612 1,643 1,674 1,908 2,067 2,418 2,756 2,862 3,286 3,348 3,627 4,134 4,836 4,929 5,724 6,201 6,572 7,254 8,268 9,858 10,881 12,402 14,508 14,787 18,603 19,716 21,359 21,762 24,804 29,574 37,206 42,718 43,524 44,361 59,148 64,077 74,412 85,436 88,722 128,154 177,444 192,231 256,308 384,462 576,693 768,924 1,153,386 and 2,306,772, with no remainder.
Since 2,306,772 cannot be divided by just 1 and 2,306,772, it is not a prime number.