Below are the data of a virtual full-frame (26 x 24 mm) lens, which produces the same field-of-view (FOV) and the same depth-of-field (DOF) as the iPhone. An imagineary full-frame camera with this lens and the given pixel size would produce an image of similar resolution (megapixels) and exposure (brightness), provided exposure time and ISO setting are the same as on the iPhone.
For comparison: A full frame DSLR (Canon EOS 5D Mk III) with 22.8 mega pixels has a pixel size of 6.25 µm - roughly 5 times the size of the iPhone’s pixel. Consequently, noise and dynamic range are much better.
All iPhones have an aspect ratio (width / height) of 4: 3, which is slightly different from full-frame format (3: 2). Therefore, any conversion to an equivalent full-frame lens can only be a (good) approximation.