In https://developer.garmin.com/connect-iq/core-topics/mobile-sdk-for-android/ under the Supported Data Types there's:
Java int, Integer => Monkey C Integer.
However in Monkey C Integer is Number or Long, so IMHO this is a bug in the documentation and the Monkey C data type should be Number.
The same error is made for long:
Java long, Long => Monkey C Integer, Long (If the value of the long is small enough to be represented as an integer, it will be converted to save space.)
However here too Integer should be changed to Number.