NTPMaxInt = 4294967297.0;

NTPMaxInt is a constant value used in translating NTP seconds and fractional seconds in a TIdSNTP instance to or from a native Delphi TDateTime value. 

NTPMaxInt is used in TIdSNTP methods that convert TDateTime values to its representation as a number of seconds, and in methods that convert a number of seconds to its representation as a TDateTime value.