Custom Objects API Call org_contact_id Not able to pass as BigInt

We are using Node JS to create the Custom Object When we pass org_contact_id as Int We are not able to run the API because Int only can take 16 Digits. We tried using BigInt But the 19 Digit Number got Converted to 19 Digit Number with N at the end. And we are not able to pass this in API its throws error

var iDa=BigInt("1720790203738025984");

const data = JSON.stringify({
    "data": {
      "reg_no": null,
      "booking_date": "02-09-2023",
      "mobile_no": "8870777",
      "type": "With Booking",
      "dealer_code": "DLR-CHN-00001",
      "booking_id": "RV23010",
      "dealer_city": "Chennai",
      "pin": "625011",
      "sale_date": "02-09-2023",
      "chassis_no": "AS2257131",
      "chasis_no": "MZMBU1013P0020772",
      "color_code": "GRY",
      "email": "",
      "customer_city": "Madurai",
      "loc_city": "Madurai",
      "customer_state": "TAMIL NADU",
      "address1": "26A  MADURAI SOUTH",
      "loc_code": "DLR-MAD-0063",
      "invoice_no": "MDU/23-24/-334",
      "model_code": "R400RRCP1CW",
      "name": "AK N",
      "dealer_name": " Communication",
      "location": "Madurai",
      "dealer_state": "TAMIL NADU"


Converted Number: 1720790203738025984n

We had tried a way where we are combining the BigInt to get the entire org_contact_id 19 digit number and we are converting it into string throught toString() - Function.prototype.toString() - JavaScript | MDN
To get the format that won’t lead to error while calling APIs
Hope this helps