8 Standard DataTypes 
8.27 Int64
This Built-in DataType defines a value that is a signed integer between −9 223 372 036 854 775 808 and 9 223 372 036 854 775 807 inclusive.
Online versions of OPC UA specifications and information models.
This Built-in DataType defines a value that is a signed integer between −9 223 372 036 854 775 808 and 9 223 372 036 854 775 807 inclusive.