Answer
$679,156$ seconds $\approx189~h$. That is almost $8$ days.
Work Step by Step
$1~s$ ______ $3,000,000$ passwords
$x~s$ ______ $2,037,468,266,496$ passwords
$3,000,000x=1\times2,037,468,266,496$
$x=\frac{2,037,468,266,496}{3,000,000}$
$x\approx679,156$
$1~s=3600~h$
$679,156~s=(679,156~s)\frac{1~h}{3600~s}\approx189~h$
