Data type of the argument of the function '837' did not match the required data type of '[BIGINT]'

Data type of the argument of the function '837' did not match the required data type of '[BIGINT]'

Hello, am testing the below code in Zoho desk Sandbox and it's giving me the error "Data type of the argument of the function '837' did not match the required data type of '[BIGINT]'"

Anyone can help?

// Get the Registration Number from the child ticket
ticket_response = zoho.desk.getRecordById(854135090,"tickets","Id");
info ticket_response;
registrationNumber = ticket_response.get("ACI Registration Number");
// Convert registrationNumber to BIGINT if necessary
registrationNumber = registrationNumber.toLong();
// Search for parent tickets with "ACI" in the subject and the same registration number
searchCriteria = "(Subject.contains:ACI) AND (ACI Registration Number:" + registrationNumber + ")";
parentTickets = zoho.desk.searchRecords(854135090,"Tickets",searchCriteria);
// If a parent ticket is found, link it to the child ticket
if(parentTickets.size() > 0)
{
parentTicketId = parentTickets.get(0).get("Id");
linkTickets = zoho.desk.update(854135090,"Tickets","Parent Ticket ID",parentTicketId);
}