A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 7847532 can be evenly divided by 1 2 3 4 6 7 9 11 12 14 18 19 21 22 28 33 36 38 42 44 57 63 66 76 77 84 99 114 126 132 133 149 154 171 198 209 228 231 252 266 298 308 342 396 399 418 447 462 532 596 627 684 693 798 836 894 924 1,043 1,197 1,254 1,341 1,386 1,463 1,596 1,639 1,788 1,881 2,086 2,394 2,508 2,682 2,772 2,831 2,926 3,129 3,278 3,762 4,172 4,389 4,788 4,917 5,364 5,662 5,852 6,258 6,556 7,524 8,493 8,778 9,387 9,834 11,324 11,473 12,516 13,167 14,751 16,986 17,556 18,774 19,668 19,817 22,946 25,479 26,334 29,502 31,141 33,972 34,419 37,548 39,634 45,892 50,958 52,668 59,004 59,451 62,282 68,838 79,268 93,423 101,916 103,257 118,902 124,564 137,676 178,353 186,846 206,514 217,987 237,804 280,269 356,706 373,692 413,028 435,974 560,538 653,961 713,412 871,948 1,121,076 1,307,922 1,961,883 2,615,844 3,923,766 and 7,847,532, with no remainder.
Since 7,847,532 cannot be divided by just 1 and 7,847,532, it is not a prime number.