LCM of 2 and 5 by Prime Factorization Prime factorization of 2 and 5 is (2) = 21 and (5) = 51 respectively. LCM of 2 and 5 can be obtained by multiplying prime factors raised to their respective highest power, i.e. 21 × 51 = 10. Hence, the LCM of 2 and 5 by prime factorization is 10.