In general, you cannot.
The prime factorization.
91 cannot be in the prime factorization of any number because it is not a prime number itself.
No. Each composite number has its own unique prime factorization.
Keep dividing the original number by smaller prime numbers until the results are all prime.
Every composite number has its own unique prime factorization.
A rational number is, by definition, the answer from dividing one integer by another.
It is: 2*2*5*7 = 140 by dividing it by each prime number that has no remainder