2.27 It can be shown (see any book on number theory) that if gcd(m,n) d(mn) d(n)d(n). Using this property, the property developed in the preceding problem, and the property that (p) p-1 for p prime, it is straightforward to determine the value of (n) for any n. Determine the following , (29) 1 then b, (51) (455) d. (616)