A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1896580 can be evenly divided by 1 2 4 5 7 10 14 19 20 23 28 31 35 38 46 62 70 76 92 95 115 124 133 140 155 161 190 217 230 266 310 322 380 434 437 460 532 589 620 644 665 713 805 868 874 1,085 1,178 1,330 1,426 1,610 1,748 2,170 2,185 2,356 2,660 2,852 2,945 3,059 3,220 3,565 4,123 4,340 4,370 4,991 5,890 6,118 7,130 8,246 8,740 9,982 11,780 12,236 13,547 14,260 15,295 16,492 19,964 20,615 24,955 27,094 30,590 41,230 49,910 54,188 61,180 67,735 82,460 94,829 99,820 135,470 189,658 270,940 379,316 474,145 948,290 and 1,896,580, with no remainder.
Since 1,896,580 cannot be divided by just 1 and 1,896,580, it is not a prime number.