True
Given, a is divisible by b.
Let b=p1.p2, where p1 and p2 are primes.
Since, a is divisible by b, a is a multiple of b
i.e. a = mb
⇒ a = m . p1.p2
or a=cp2=dp1, where c=mp1,d=mp2
⇒ a is a multiple of p1 as well as p2.
Hence, a is divisible by each factor b.