The number 7,757,820 can be evenly divided by 1 2 3 4 5 6 7 9 10 12 14 15 18 20 21 28 30 35 36 42 45 47 60 63 70 84 90 94 105 126 131 140 141 180 188 210 235 252 262 282 315 329 393 420 423 470 524 564 630 655 658 705 786 846 917 940 987 1,179 1,260 1,310 1,316 1,410 1,572 1,645 1,692 1,834 1,965 1,974 2,115 2,358 2,620 2,751 2,820 2,961 3,290 3,668 3,930 3,948 4,230 4,585 4,716 4,935 5,502 5,895 5,922 6,157 6,580 7,860 8,253 8,460 9,170 9,870 11,004 11,790 11,844 12,314 13,755 14,805 16,506 18,340 18,471 19,740 23,580 24,628 27,510 29,610 30,785 33,012 36,942 41,265 43,099 55,020 55,413 59,220 61,570 73,884 82,530 86,198 92,355 110,826 123,140 129,297 165,060 172,396 184,710 215,495 221,652 258,594 277,065 369,420 387,891 430,990 517,188 554,130 646,485 775,782 861,980 1,108,260 1,292,970 1,551,564 1,939,455 2,585,940 3,878,910 and 7,757,820, with no remainder.
Since 7,757,820 cannot be divided by just 1 and 7,757,820, it is a composite number.