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No, 21 is not a Prime number. A prime number is defined as a natural number greater than 1 that has no positive divisors other than 1 and itself. Since 21 can be divided evenly by 1, 3, 7, and 21, it has divisors other than 1 and itself, making it a composite number.
What else can I help you with?
Why isn't one a primenumber?
It doesn't have two factors.
What is eleven twelfths simplified?
11/12 cannot be simplified - because 11 is a primenumber.
What is simplest form for 67 over 90?
It's already in its simplest form - 67 is a primenumber.
What is 12 over 43 in simplest form?
It's already in its simplest form - since 43 is a primenumber.
Which one does not belong 23 34 45?
23 doesnot belong because it is a primenumber. Its factors are 1 and itself only.34 and 45 are compositenumbers. Their factors aside from 1 and themselves are:34 = 2, 1745 = 3, 5, 9, 15,
What is the 1000th primenumber?
7919
Is 5 a primenumber?
Yes.
How many factors does a primenumber have?
Two.
Is 87 a primenumber?
Nope - it can be divided by 3.
Why isn't one a primenumber?
It doesn't have two factors.
Is 28 a primenumber?
No, it is an even number and therefore can be at least divided by 2.
Give three primenumber whose differense is 2?
3, 5, and 7.
What is eleven twelfths simplified?
11/12 cannot be simplified - because 11 is a primenumber.
What is simplest form for 67 over 90?
It's already in its simplest form - 67 is a primenumber.
What is 18 over 29 in simplest form?
18/29 cannot be simplified - because 29 is a primenumber !
Is -2 primenumber or not?
I could bore you with a long mathematical explanation (ask if you want one), but to simplify things, 2 is a prime number.
What is 12 over 43 in simplest form?
It's already in its simplest form - since 43 is a primenumber.
