A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 7581760 can be evenly divided by 1 2 4 5 8 10 16 19 20 29 32 38 40 43 58 64 76 80 86 95 116 145 152 160 172 190 215 232 290 304 320 344 380 430 464 551 580 608 688 760 817 860 928 1,102 1,160 1,216 1,247 1,376 1,520 1,634 1,720 1,856 2,204 2,320 2,494 2,752 2,755 3,040 3,268 3,440 4,085 4,408 4,640 4,988 5,510 6,080 6,235 6,536 6,880 8,170 8,816 9,280 9,976 11,020 12,470 13,072 13,760 16,340 17,632 19,952 22,040 23,693 24,940 26,144 32,680 35,264 39,904 44,080 47,386 49,880 52,288 65,360 79,808 88,160 94,772 99,760 118,465 130,720 176,320 189,544 199,520 236,930 261,440 379,088 399,040 473,860 758,176 947,720 1,516,352 1,895,440 3,790,880 and 7,581,760, with no remainder.
Since 7,581,760 cannot be divided by just 1 and 7,581,760, it is not a prime number.