As the power function is in SQL Anywhere 17.0.10.5866 defined only for the double data type, I wrote a new power function only for integers called power_int: create or replace function power_int( @int decimal(127,0), @j decimal (127,0) ) returns decimal(127,0) as begin declare @i decimal (127,0) declare @a decimal (127,0) if @j=0.0 set @int=1.0 set @i=1.0 set @a=@int while @i<=@j1.0 begin set @int=@int*@a set @i=@i+1.0 end return @int end; The function generates for smaller results correct values. If the result has more the 33 digits it becomes wrong: select power_int (16,27) 324518553658426726783156020576200 wrong result 324518553658426726783156020576256 correct select power_int (2,107) 162259276829213363391578010288100 wrong result 162259276829213363391578010288128 correct While power_int (16,26) and (2,106) gave the correct result. In ASE 16.0.x the function works fine if instead of decimal(127,0) decimal(38,0) will be used. Many thanks Robert asked 16 Sep '19, 11:02 Robert Krats... 
set option PUBLIC.precision = 120; and retry answered 17 Sep '19, 14:08 JBSchueler Volker Barth Works fine, never heard about this option. Many thanks
(18 Sep '19, 02:44)
Robert Krats...
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Default precision and scale are PUBLIC database options that can be set. Check the documentation for more information.
(18 Sep '19, 10:04)
JBSchueler

Just curious  why not use integer data types? I seem to recall Decimal only being accurate to 32 digits, but haven't researched it.
The bigint data type is only usable up to a maximum of 9,223,372,036,854,775,807 (19 digits). The procedure is part of a hexadecimal to decimal conversation with up to 32 digits. So bigint may be to small.