问Kotlin错误:无法使用提供的参数调用以下任何函数

EN

None of the following functions can be called with the arguments supplied: 
public final operator fun div(other: Byte): Int defined in kotlin.Int
public final operator fun div(other: Double): Double defined in kotlin.Int
public final operator fun div(other: Float): Float defined in kotlin.Int
public final operator fun div(other: Int): Int defined in kotlin.Int
public final operator fun div(other: Long): Long defined in kotlin.Int
public final operator fun div(other: Short): Int defined in kotlin.Int

mTimerTextview.setText(millisUntilFinished.toInt()  / 1000.toString() + "s")

startQuizButton.setOnClickListener {
            constraintChild.visibility = View.VISIBLE
            startQuizButton.visibility = View.GONE
            score = 0
            totalAttempt = 0
            mStatusTextview.text = "0/0"
            newQuestion()
            countDownTimer = object : CountDownTimer(30100, 1000) {
                override fun onTick(millisUntilFinished: Long) {
                    mTimerTextview.setText(millisUntilFinished.toInt()  / 1000.toString() + "s")
                }