It's roughly 13 times too light to classify as a brown dwarf, but we could call it a grey dwarf and define the pair as a double star.
It would be a rather unorthodox pairing for having other planets orbit the primary not far outside of the secondary's orbit.
On the plus side, this would give our system a lot of new dwarf planets as Jupiter's moons are upgraded, possibly even a planet or two to compensate for the loss of Jupiter, depending on the exact orbital calculus.
You'd be left with rather exotic isotopes.
Do you figure with could stuff in so many neutrons that the electron hits them and crashes? What would take take, an atomic mass of a few billion mu?