iPhone camera specs (true vs. equivalent)

I would like to better understand the specs of the iphone camera. To me, it is not clear which of the specs apple is providing are meant as "full frame equivalent" and which are true specs.

Let us take the iPhone 15 pro max as an example. Here, apple provides "24 mm equivalent f/1.78". What does that mean?

If my research is correct, the sensor is 9.8 x 7.3 mm. So this leads to the first question: which crop factor has apple applied in order to calculate equivalent values? As compared to full frame (36 x 24 mm), along the x-axis, the crop factor is 3.67 and, along the y-axis, the crop factor is 3.29. Let us assume, apple refers to the diagonal, which would be a crop factor of 3.55.

Applying this factor to the focal length results in a true focal length of 6.8 mm.

My second question is: what is the maximum aperture of the iPhone lens? If f/1.78 were also an "equivalent" number, then the true f-value would be 0,50, corresponding to an aperture diameter of 13.6 mm, which would be really impressive. However, I suspect that, unlike focal length, 1.78 is the true f-value, corresponding to a diameter of 3.8 mm and an equivalent f/6.3.

Which one is it?