Can an apk file be written to any type of NFC tag Is it possible to write an apk file to a NFC tag for it to be downloaded when a user desires? bWe are trying to create a solution in which our reps in the field can simply turn on NFC in specific locations then download an apk file for our custom app. Normally simply providing a link to the file on our server would be ideal by using URI type of tag however these devices (Android phones) may not have WiFi nor Cellular data connection in order to install the app's apk file via a link embedded to the NFC tag.

The NFC tags would be "installed" by a separate team. While it makes perfect sense to have our reps preloaded with the application, the consideration is to also allow customers to download the apk file for installation on their device if they desire as well. The apk is a 6 - 7 MB file.
Some resources I've found regarding NFC tags seems to indicate this would not be possible:

NFC Chip Types
The highest memory available is only about 7600 bytes. Which is quite a bit more than most apks.

NFC Data Exchange Format
The standardized data format specification that is supported by NFC Devices.


  At a basic level, an NDEF record contains two components: (1) the data and (2) a descriptor of that data which is used to contextualize the data. [ . . . ] NDEF supports a fairly limited set of actions. More complex actions can be implemented with customized software running on the touching device.


So the default actions that may be supported by NFC devices are:


Url
Text
Email
VCard
Phone
SMS
URI


In order to support a non-standard action, you would have to completely implement that in a separate app. Then to transport your apk, it would have to be within the data limitations of all modern NFC tags.