Q: Is 21,875 a Prime Number?
A: No, 21,875 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 21875 can be evenly divided by 1 5 7 25 35 125 175 625 875 3,125 4,375 and 21,875, with no remainder.
Since 21,875 cannot be divided by just 1 and 21,875, it is not a prime number.