toggle the bits and return the unsigned 32 bit integer of same. Not All test cases running

I am solving a ‘hackerRank’ coding challenge (basic) using JavaScript. the problem is,
You will be given a list of 32 bit unsigned integers. Flip all the bits (1->0 and 0->1) and return the result as an unsigned integer.

here is my code (I aware that i tried a cumbersome way and there is a very easy single line to code as well return (~n >>> 0)

function flippingBits(n) {
  function dtb(num){
    let rem = 0 ;
    let i = 0;
    let op = 0;

    while(num !== 0){
      rem = num % 2;
      op = op + (rem*(Math.pow(10,i)));
      i++;
      num = Math.floor(num/2);
    }
    return String(op).padStart(32,'0');
  }

  function toggle(n){
    let newOp = dtb(n);
    let finalOp = '';
    for(let i=0;i<newOp.length;i++){
      if(newOp[i] === '1'){
        finalOp += '0';
      } else {
        finalOp += '1';
      }
    }
    return finalOp;
  }

  function btd(n){
    let num = toggle(n);
    let op = 0;
    for(let i=0;i<num.length;i++){
      op = op + (Math.pow(2,(num.length- 1)-i)*num[i]);
    }
    return op;
  }

  return btd(n);
}

the inputs that passed
enter image description here

the inputs that failed

Input (stdin)
3
0
802743475
35601423

my Output (stdout)
4294967295
4292350879
4293886735

Expected Output
4294967295
3492223820
4259365872