has only the prime divisors
and
.
Every divisor of
is therefore of the form
,
where
and
are elements of {0,1,2,3}. Since there
are
choices for
and
choices for
, there are
divisors of
. That isn't necessary to know. But
in the product of all
divisors of
,
or
, and
or
occur exactly
times each.
Since
and
both occur
times each in the product
of all divisors, the product of the divisors must be
, choice a)
Edwin