No way you can improve it. SAS uses floating point representation. For more information please refer to the following link.

https://support.sas.com/document ... .htm#a000695157.htm

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327  data _null_;
328    x=123456789123456789;
329    z=123456789123456800;
330    r=x/z;
331    put x= 25.2 z=25.2 r= 25.23;
332    run;

x=123456789123456800.00 z=123456789123456800.00 r=1.00000000000000000000000
NOTE: DATA statement used (Total process time):
      real time           0.00 seconds
      cpu time            0.01 seconds