Interesting, I couldn't find that anywhere. I wonder where they got that info.
Amending this, it appears to come from
https://www.documentcloud.org/documents/2175187-Annoying Orange.html which was his official paper filing for becoming a presidential candidate.
I counted 534 different businesses listed, 28 of which are listed as no longer existing which is 5.24%.
Another interesting tidbit is that the part below that says "Filer's Employment Assets and Income" (different than "Filer's Positions Held Outside United States Government" apparently? Idk how) of which there are 168 businesses listed, 66 are listed as having no income. Assuming I haven't terribly misunderstood something (please let me know if I have) either that means they're non-functional and just "companies" made to store money/real estate (which is quite commonplace, chances are most if not all of them are this) or they're actually unprofitable businesses (Makes sense that these wouldn't be listed anymore)