A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1572960 can be evenly divided by 1 2 3 4 5 6 8 10 12 15 16 20 24 29 30 32 40 48 58 60 80 87 96 113 116 120 145 160 174 226 232 240 290 339 348 435 452 464 480 565 580 678 696 870 904 928 1,130 1,160 1,356 1,392 1,695 1,740 1,808 2,260 2,320 2,712 2,784 3,277 3,390 3,480 3,616 4,520 4,640 5,424 6,554 6,780 6,960 9,040 9,831 10,848 13,108 13,560 13,920 16,385 18,080 19,662 26,216 27,120 32,770 39,324 49,155 52,432 54,240 65,540 78,648 98,310 104,864 131,080 157,296 196,620 262,160 314,592 393,240 524,320 786,480 and 1,572,960, with no remainder.
Since 1,572,960 cannot be divided by just 1 and 1,572,960, it is not a prime number.