gatling testing - random 32 digit number is created for each user

I am using Gatling for load testing and I want to create a 32 digit random number for an order

This is what I have

val feeder = Iterator.continually(Map("orderNumber" -> (Random.alphanumeric.filter(_.isDigit).take(32).mkString)))
  val scn = scenario("Typical customer order flow")
    .feed(feeder)
    .exec(
      http("price basket")
        .post("/v1/totals/${orderNumber}")
        .body(ElFileBody("gatling/samplePricingRequestBody.xml")).asXml
        .check(
          status.is(200),
          xpath("/priceOrder")))

I see that it does create the random 32 digit number for the order but when I run Gatling is shows that it is failing

error message is

body= 5101100Luhn check failure, invalid character, incorrect lengthBad Request[orderToken] <<<<<<<<<<<<<<<<<<<<<<<<< []