Answer: Two numbers are said to be relatively prime if they share no common factors other than 1. To find a number that is relatively prime to 63, we need to find a number that has no factors in common with 63 other than 1.
The prime factorization of 63 is 3 * 3 * 7. Therefore, any number that is divisible by 3 or 7 is not relatively prime to 63.
For example, 21 is not relatively prime to 63 because both 21 and 63 are divisible by 3. Similarly, 35 is not relatively prime to 63 because both 35 and 63 are divisible by 7.
One number that is relatively prime to 63 is 25. 25 is not divisible by 3 or 7, and therefore has no common factors with 63 other than 1.