Whenever we are retrieving values for
Currency column, it only returns its value in Numeric format but doesn't returns Currency Type.
As we know a Currency column can be set to contain only one type of currency so first retrieve Currency Type by its column property
The above REST call return 4 digit LCID (Locale ID) which is universal for each type of locale e.g. 1033 is for English - United States so its currency would be USD.
You can find complete list of LCID in the below link.