We show that Artin's constant and two related number-theoretic quantit
ies can be computed to t bits of precision using t(3+o(1)) bit operati
ons. The factor implied by the symbol o(1) depends on the cost of the
underlying arithmetic, but for practical purposes can be taken as log
t. As a by-product of this work, we estimate the complexity of computi
ng Bernoulli numbers and evaluating the Riemann zeta function at posit
ive integers. We also give examples of constants that seem hard to com
pute, such as Brun's twin prime constant and the exact density of prim
es for which a given base is a primitive root. This last cannot be com
puted quickly unless factorization of certain RSA moduli is easy. (C)
1997 Elsevier Science B.V.