Q: Is 20,640 a Prime Number?
A: No, 20,640 is not a prime number.
A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 20640 can be evenly divided by 1 2 3 4 5 6 8 10 12 15 16 20 24 30 32 40 43 48 60 80 86 96 120 129 160 172 215 240 258 344 430 480 516 645 688 860 1,032 1,290 1,376 1,720 2,064 2,580 3,440 4,128 5,160 6,880 10,320 and 20,640, with no remainder.
Since 20,640 cannot be divided by just 1 and 20,640, it is not a prime number.