function mnozhText($num, $end1, $end2, $end5) {
$num = abs($n) % 100;
$numN = $n % 10;
if ($num > 10 && $num < 20) return $end5;
if ($numN > 1 && $n1 < 5) return $end2;
if ($numN == 1) return $end1;
return $end5;
}
echo '5' . mnozhText(5, 'час', 'часа', 'часов');