I'm experiencing some trouble in understanding the evolution of the Apple number of shares.
In particular, I am looking at its 10-Qs of 27 June 2020 and 26 December 2020. Here, I read that there were 4,275,634,000 shares in July 2020 and 16,788,096,000 in January 2021, which I understand it means that Apple has almost quadrupled its number of shares over six months.
By googling "Apple number of shares" I didn't find any evidence of the number of shares being 4B in July 2020. Indeed, it seems that they were around 17B.
Could someone please help me understanding what I am reading in the SEC filings? Why in the June 2020 report 4B shares were reported?