This function will return true if expr is an expression of the form returned by the function ifactor, and false otherwise.

The numbers $0$, $1$, and $\mathrm{-1}$ are considered to be of type facint, but all other integers and rationals must be passed through ifactor before type/facint will return true when applied to them.

$a≔\mathrm{ifactor}\left(2520\right)$

$a≔{\left(2\right)}^3{\left(3\right)}^2\left(5\right)\left(7\right)$

$\mathrm{type}\left(a\,\mathrm{facint}\right)$

$\mathrm{true}$

$b≔\mathrm{ifactor}\left(\frac{81}{8}\right)$

$b≔\frac{{\left(3\right)}^4}{{\left(2\right)}^3}$

$\mathrm{type}\left(b\,\mathrm{facint}\right)$

$\mathrm{true}$

$\mathrm{type}\left(1\,\mathrm{facint}\right)$

$\mathrm{true}$

$\mathrm{type}\left(5\,\mathrm{facint}\right)$

$\mathrm{false}$

$\mathrm{type}\left(\mathrm{ifactor}\left(5\right)\,\mathrm{facint}\right)$

$\mathrm{true}$