A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 7720596 can be evenly divided by 1 2 3 4 6 9 12 13 18 26 27 36 39 47 52 54 78 81 94 108 117 141 156 162 169 188 234 243 282 324 338 351 423 468 486 507 564 611 676 702 846 972 1,014 1,053 1,222 1,269 1,404 1,521 1,692 1,833 2,028 2,106 2,444 2,538 3,042 3,159 3,666 3,807 4,212 4,563 5,076 5,499 6,084 6,318 7,332 7,614 7,943 9,126 10,998 11,421 12,636 13,689 15,228 15,886 16,497 18,252 21,996 22,842 23,829 27,378 31,772 32,994 41,067 45,684 47,658 49,491 54,756 65,988 71,487 82,134 95,316 98,982 142,974 148,473 164,268 197,964 214,461 285,948 296,946 428,922 593,892 643,383 857,844 1,286,766 1,930,149 2,573,532 3,860,298 and 7,720,596, with no remainder.
Since 7,720,596 cannot be divided by just 1 and 7,720,596, it is not a prime number.