Provide an unhash function complements hash

unhash example.js

function hash(s)
{
  let hash = 7
  let letters = "acdfgilmnoprstuw"
  for(i = 0; i < s.length; i++)
  {
    hash = (hash * 23 + letters.indexOf(s[i]))
  }
  return hash
}

function unhash(num)
{
  var unhash = []; //array to return the string
  var nums = []; //array to store the numbers corresponding to letters
  nums[0] = num; //assign num as first element of array
  var letters = "acdfgilmnoprstuw";

  //traversal to fill nums array
  for(let i = 0; i < 10; i++)
  {
    num = parseInt((num / 23 ));
    nums.push(num);
  }
  nums.push(7); //assign 7 to the last element of array
  nums.reverse(); //reverse array to have it from beginning

  //fills unhash array with the corresponding letters
  for (let i = 1; i <= 11; i++) {
    unhash.push(letters.charAt(nums[i]-(nums[i-1]*23)));
  }
  return unhash.join(''); //return the string
}

console.log(unhash('292681030017238'))

unhash(292681030017238) == crowdgifts