Q: Is 21,438 a Prime Number?
A: No, 21,438 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 21438 can be evenly divided by 1 2 3 6 9 18 27 54 397 794 1,191 2,382 3,573 7,146 10,719 and 21,438, with no remainder.
Since 21,438 cannot be divided by just 1 and 21,438, it is not a prime number.