7
15
63 / 3 = 21The middle number is 21The odd numbers next to 21 are 19 and 2319 + 21 + 23 = 63
23 Prime numbers are odd numbers and 21=3x7
It is an odd number. It is not prime. Its factors are 1, 3, 7 and 21. It is positive.
No because 2 is an even number which is also a Prime number that has only two factors which are itself and one.
No, it cannot be done. As 23 is odd, two numbers used would have to be one odd and one even. As 2 is the only even prime number and 21 + 2 equals 23, but 21 is not a prime number, it cannot be done.
No.Prime numbers are numbers that can only be divided evenly by itself and 1.For example, the number 7 can only be divided by 7 and 1.Odd numbers are numbers that end in (or are) 1, 3, 5, 7, or 9.For example, the number 21 is odd since it ends in a 1, but it is not prime because itcan be divided by 1, 21, 7, and 3. (7 times 3 = 21.)2 is a prime number and is even not odd - it is the only even prime number.
If an odd number has more than two factors then it is a composite number but if it has only two factors then it is a prime number. Although all prime numbers are odd except for 2 many more odd numbers are composite numbers having more than two factors as for example 21 is an odd number whose factors are 1, 3, 7 and 21.
3 x 7 = 21, since both factors are prime, that is the prime factorization of 21.
13 is prime so it is not the number. 15 is the product of 3 and 5, two prime numbers, so it fits the conditions. 17 is prime so it is not the number. 19 is prime so it is not the number. 15 is the only odd number between 11 and 21 that fits the conditions. However, if 21 is included in the range, it also is the product of two prime numbers: 3 x 7.
21 = 3 x 7 both 3 and 7 are prime numbers
21 is an odd composite number