A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 8288896 can be evenly divided by 1 2 4 7 8 11 14 16 22 28 29 32 44 56 58 64 77 88 112 116 128 154 176 203 224 232 308 319 352 406 448 464 616 638 704 812 841 896 928 1,232 1,276 1,408 1,624 1,682 1,856 2,233 2,464 2,552 3,248 3,364 3,712 4,466 4,928 5,104 5,887 6,496 6,728 8,932 9,251 9,856 10,208 11,774 12,992 13,456 17,864 18,502 20,416 23,548 25,984 26,912 35,728 37,004 40,832 47,096 53,824 64,757 71,456 74,008 94,192 107,648 129,514 142,912 148,016 188,384 259,028 285,824 296,032 376,768 518,056 592,064 753,536 1,036,112 1,184,128 2,072,224 4,144,448 and 8,288,896, with no remainder.
Since 8,288,896 cannot be divided by just 1 and 8,288,896, it is not a prime number.