Given numbers are 6 and 21.
The prime factorization of 6 and 21 gives:
Here, 31 is the smallest power of the common factor 3.
Therefore, the H.C.F of these two integers = 3
21 × 31 × 71 are the greatest powers of the prime factors 2, 3 and 7 respectively involved in the given numbers.
Now, L.C.M of 6 and 21 is 2 ×3 × 7 = 42