CFLib.org – Common Function Library Project

Description:
Returns True if the specified number is a perfect number. A perfect number is an integer greater than zero whose factors less than the number all add up to the number (i.e. 6 is a perfect number 3+2+1=6).

Return Values:
Returns a Boolean value.

Example:

<CFOUTPUT>
Is 6 a perfect number? #YesNoFormat(IsPerfectNumber(6))#<BR>
Is 12 a perfect number? #YesNoFormat(IsPerfectNumber(12))#<BR>
</CFOUTPUT>

Parameters:

Full UDF Source:

/**
 * Returns True if the specified number is a perfect number.
 * 
 * @param number      Integer greater than zero to test. 
 * @return Returns a Boolean value. 
 * @author Rob Brooks-Bilson (rbils@amkor.com) 
 * @version 1, September 6, 2001 
 */
function IsPerfectNumber(number)
{
  Var i=0;
  Var factors = "";
  Var factorArray=0;
  Var sum=0;
  if (number lt 1){
    return False;
    break;
  }  
  for (i=1; i LTE number/2; i=i+1) {
    if (Int(number/i) EQ number/i) {
      factors = ListAppend(Factors, i);
    }
  }  
  factorArray=ListToArray(factors);
  sum=ArraySum(factorArray);
  if (sum eq number){
    return True;
  }
  else{
    return False;
  }
}