14 million may sound like a lot but it is as official as it can be: the figure has been provided by military sources, which have been monitoring the protests from the air in helicopters.
The opposition movement Tamarod claims to have gathered no less than 22 million signatures for the resignation of President Morsi, many more than the 13 million votes gathered by this one in the elections and almost half of the country's electoral census.
In spite of all this, so far Morsi and his Muslim Brotherhood party, which have become in practice continuity of the Mubarak regime, reject resignation or elections, even if they admit "some mistakes". Morsi has fled from Cairo to some military barracks in the country and denounces the protests as a "coup attempt".
In spite of eight people being killed in the previous days and reports of some gang rapes, the protests seem to be largely peaceful and enthusiastic, maybe overconfident on their numerical strength. The demand is clearly a government that ensures freedom and social justice, no more, no less, and clearly Morsi and the Brotherhood have failed completely in both accounts.
Sources: Yahoo! News (link 1, link 2), Reuters, NBC.