A factor which is a prime number is called a prime factor.

---

Theorem : Every composite number can be factorised or expressed as a product of primes,and this factorization is unique except for the order in which the prime factors occur.

---

Prime Factorization :Express a natural number as a product of its prime factors is called prime factorization.

e.g. (i) 630 = 2 x 3² x 5 x 7
(ii) 90 = 2 x 3 ²x 5
(iii) 196 = 2² x 7²

---

Note :Prime factorization is helpful to find L.C.M and H.C.F and to check irrationality.