A certain disk can read data at a rate of $214\mathrm{.}1$ MB$/$s$.$ How many books can be read in $7$ seconds if an "average" book has

$75$ pages,

$20$ lines per page,

$8$ words per line,

$7$ characters per word,

and each character is one of $238$ different characters where the fewest number of bits are used to represent each character?