kotlin product of odd or even integers

Question

The problem I'm working on accepts a number string and will output the product of the odd or even numbers in the string. While the product of purely number string is working fine, my code should also accept strings that is alphanumeric (ex: 67shdg8092) and output the product. I'm quite confused on how I should code the alphanumeric strings, because the code I have done uses toInt().

Here's my code:

fun myProd(Odd: Boolean, vararg data: Char): Int {
    var bool = isOdd
    var EvenProd = 1
    var OddProd = 1
    for (a in data) 
    {
      val intVal = a.toString().toInt()
      if (intVal == 0) 
      {
        continue
      }
      if (intVal % 2 == 0)
      {
        EvenProd *= intVal
      }
      else 
      {
        OddProd *= intVal
      }
    }
    if(bool == true) return OddProd
    else return EvenProd
}