A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 9628476 can be evenly divided by 1 2 3 4 6 11 12 13 22 26 31 33 39 44 52 62 66 78 93 124 132 143 156 181 186 286 341 362 372 403 429 543 572 682 724 806 858 1,023 1,086 1,209 1,364 1,612 1,716 1,991 2,046 2,172 2,353 2,418 3,982 4,092 4,433 4,706 4,836 5,611 5,973 7,059 7,964 8,866 9,412 11,222 11,946 13,299 14,118 16,833 17,732 22,444 23,892 25,883 26,598 28,236 33,666 51,766 53,196 61,721 67,332 72,943 77,649 103,532 123,442 145,886 155,298 185,163 218,829 246,884 291,772 310,596 370,326 437,658 740,652 802,373 875,316 1,604,746 2,407,119 3,209,492 4,814,238 and 9,628,476, with no remainder.
Since 9,628,476 cannot be divided by just 1 and 9,628,476, it is not a prime number.