Convert integer to string preserving order
PowerShell, 185

$s=32767
function f($x){$a='';while($x){$r=$x%$s;$a+=[char]($r+$s)
[long]$x=[bigint]::divide($x,$s)};$a}
function g($x){$a=0;0..($x.length-1)|%{$a+=($x[$_]-$s)*[bigint]::pow($s,$_)};$a}


Ungolfed

$shift = 32767

function f($number) {
    $string = ''
    while($number) {
        $remain = $number % $shift
        $string += [char]($remain+$shift)
        [long]$number = [bigint]::divide($number, $shift)
    }
    $string
}

function g($string) {
    [long]$number = 0
    0..($string.length-1)|%{$number += ($string[$_]-$shift)*[bigint]::pow($shift, $_)}
    $number
}


At most, the output will be length 5.

&gt; f ([long]::MaxValue)
耆耟耯耟耇
&gt; g '耆耟耯耟耇'
9223372036854775807
&gt; f ([long]::MinValue)
翷翟翏翟翷
&gt; g '翷翟翏翟翷'
-9223372036854775808