My calculation of how many megapixels large sensor cameras could have if they had P&S pixel density

Okay, so as we all know, point and shoot cameras tend to have MUCH much much more pixels per sensor-area than larger sensor non-point and shoot cameras like m4/3, APS-C, or full frame cameras such as DSLR's and interchangeable lens cameras.

For example, most point and shoot cameras have sensors with a sensor size of just 1/2.3" or 1/1.7", which is miniscule compared to the much larger m4/3, APS-C, or full frame sensor sizes.  However, in spite of this, point and shoot cameras have still had nearly as many pixels as their large sensor counterparts, due to the manufacturers simply squishing way more pixels per unit area (as in, using much much much much smaller photosites than they do on large sensors).

You can find tons of point and shoot cameras with the very common, but very tiny 1/2.3" sensor size, and in the past couple years, most of these have around 14-18 megapixels, probably around 16 megapixels on average.

The Sony Cyber-Shot DSC-H200, for example, has a 1/2.3" sensor, and has 20.1 megapixels.

So, out of boredom, I clicked open the calculator in the start menu of my laptop and crunched the numbers on how many megapixels m4/3, APS-C, and full frame sensor-size cameras could theoretically have, if they were to use sensors with pixels densities as high as these point & shoot cameras have.  To do this, I just divided the sensor area of m4/3 sensors, aps-c, and full frame sensors by the sensor area of the 1/2.3" p&s sensor, and then multiplied that number by the number of megapixels of the 20.1mp Sony camera described above, and thus got the theoretical amount of megapixels that the respective m4/3, aps-c, and full frame cameras could have if they used the type of sensor of these point and shoot cameras, in terms of pixel density.

The results were as follows:

Sony Cyber-shot DSC-H200:
 20.1 megapixels
 sensor: 1/2.3"
 sensor area: 28.0735 square millimeters

If we were to make a sensor of this pixel-density at:
 m4/3 sensor size, it would have:  161.0 megapixels
 APS-C sensor size, it would have:  267.0 megapixels
 Full Frame sensor size, it would have:  618.6 megapixels

So, basically, if you "scotch-taped" (okay not literally lol, but you know what I mean), a bunch of point & shoot camera sensors together to create an m4/3, or aps-c, or full frame sized sensor out of a bunch of little p&s sensors glued together, those are the theoretical pixel amounts those sensors could have, respectively, for each of those 3 standard larger-sensor sizes.

That said, it would of course have the terrible high-iso performance, crappy dynamic range, crappy pixel-level quality etc etc problems that point and shoot cameras have, so, it would not be some magic ultimate camera by any means, but, that said, it could be somewhat interesting for creating a digital-zoom style of superzoom camera in the following way:

Basically, make a compact, fixed-lens camera (like the sony rx-1, or sigma dp or one of those sorts of cameras), with a full frame sensor, with 618 megapixels, and if let's say it has a 35mm fixed focal length lens, then you could still basically "digital-zoom" a picture to being "sorta like" 280mm at 9.6 megapixels.  Which wouldn't really be that impressize in terms of just trying to make a compact, pocketable camera that could zoom to that hard, since there are regular point and shoots these days that are small and pocketable that can zoom, optically, to these sorts of fairly high focal lengths, however, the gimmick of it would be that unlike those, which have to use very tiny, crappy little lenses, this one would be using a bigger, higher quality full frame pancake lens.  So, in theory it would maybe yield higher quality photos than an equivalent small sensor point and shoot with a typical small point and shoot lens, while still yielding similar focal range capability, albeit in digital zoom instead of optical zoom via exploiting the massive megapixel count of its sensor, and having a fixed focal length lens.

Anyways, obviously they aren't actually going to do this, but it is kind of fun hypothetical to think about.