I have recieved $calc errors at 16 digit integers, havent noticed any below that yet, so i would say it MAYBE 1-999,999,999,999,999
an example of an error at 16 digits is...
//echo -a $calc(9999999999999999 / 9)
1111111111111110.9
* there may be others below this size, i havent found one myself (havent looked hard either) *