A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 7753536 can be evenly divided by 1 2 3 4 6 7 8 9 12 14 16 18 21 24 27 28 32 36 42 48 54 56 63 64 72 84 96 108 112 126 144 168 189 192 216 224 252 288 336 378 432 448 504 576 641 672 756 864 1,008 1,282 1,344 1,512 1,728 1,923 2,016 2,564 3,024 3,846 4,032 4,487 5,128 5,769 6,048 7,692 8,974 10,256 11,538 12,096 13,461 15,384 17,307 17,948 20,512 23,076 26,922 30,768 34,614 35,896 40,383 41,024 46,152 53,844 61,536 69,228 71,792 80,766 92,304 107,688 121,149 123,072 138,456 143,584 161,532 184,608 215,376 242,298 276,912 287,168 323,064 369,216 430,752 484,596 553,824 646,128 861,504 969,192 1,107,648 1,292,256 1,938,384 2,584,512 3,876,768 and 7,753,536, with no remainder.
Since 7,753,536 cannot be divided by just 1 and 7,753,536, it is not a prime number.