integer firstInt = 5512623;
integer secondInt = ACTIVE;
integer thirdInt = 0x61EC1A;
integer fourthInt = -160693;

integer decimalValue = 125.2; // ERROR : Type mismatch -- Integer literals can't have a decimal.
integer bigValue = 3147483647; // An undocumented way to say -1,147,483,649 // Integer literals can't be larger than 2,147,483,647.
integer biggerValue = 10123456789; // An undocumented way to say -1 // Integer literals can't be larger than 2,147,483,647.

integer IsInteger(string var)
{
    integer i;
    for (i=0;i<llStringLength(var);++i)
    {
        if(!~llListFindList(["1","2","3","4","5","6","7","8","9","0"],[llGetSubString(var,i,i)]))
        {
            return FALSE;
        }
    }
    return TRUE;
}

    if ( (string) ( (integer) data) == data)
        llOwnerSay("'" + data + "' contains a valid integer");

    StringOf5Dec(string test)
    {
        return ( (integer) ("1" + test) >= 100000);
    }

    VarStringIsDecimal(string test)
    {
        integer limit = (integer) llPow(10.0, llStringLength(test) );
        return ( (integer) ("1" + test) >= limit);
    }

    integer uIsInteger(string input)
    {
        input = llStringTrim(input,STRING_TRIM); // remove leading/trailing whitespace
        // "+123" is a valid integer string but would otherwise fail, so strip leading "+" if it's there
        if (llGetSubString(input,0,0) == "+") input = llGetSubString(input,1,-1);
        return ((string)((integer)input) == input);
    }