A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 4537224 can be evenly divided by 1 2 3 4 6 8 9 12 18 24 29 36 41 53 58 72 82 87 106 116 123 159 164 174 212 232 246 261 318 328 348 369 424 477 492 522 636 696 738 954 984 1,044 1,189 1,272 1,476 1,537 1,908 2,088 2,173 2,378 2,952 3,074 3,567 3,816 4,346 4,611 4,756 6,148 6,519 7,134 8,692 9,222 9,512 10,701 12,296 13,038 13,833 14,268 17,384 18,444 19,557 21,402 26,076 27,666 28,536 36,888 39,114 42,804 52,152 55,332 63,017 78,228 85,608 110,664 126,034 156,456 189,051 252,068 378,102 504,136 567,153 756,204 1,134,306 1,512,408 2,268,612 and 4,537,224, with no remainder.
Since 4,537,224 cannot be divided by just 1 and 4,537,224, it is not a prime number.