Exception has occurred. _TypeError (type 'int' is not a subtype of type 'String')

Oi gente boa tarde, eu terminei o curso e meu código e aplicativo aparentemente estavam funcionando direitinho, mas quando eu vou clicar no botão CONTATOS lá na pagina principal do aplicativo ele carrega e dá esse erro no meu CONTACT_DAO.DART na sessão do "ID":Exception has occurred. _TypeError (type 'int' is not a subtype of type 'String')

MEU CÓDIGO:

import 'package:sqflite/sqflite.dart';
import '../../models/contact.dart';
import '../app_database.dart';

class ContactDao {
  static const String tableSql = 'CREATE TABLE $_tableName('
      '$_id INTEGER PRIMARY KEY, '
      '$_name TEXT, '
      '$_accountNumber INTEGER)';
  static const String _tableName = 'contacts';
  static const String _id = 'id';
  static const String _name = 'name';
  static const String _accountNumber = 'account_number';

  Future<int> save(Contact contact) async {
    final Database db = await getDatabase();
    Map<String, dynamic> contactMap = _toMap(contact);
    return db.insert(_tableName, contactMap);
  }

  Future<List<Contact>> findAll() async {
    final Database db = await getDatabase();
    final List<Map<String, dynamic>> result = await db.query(_tableName);
    List<Contact> contacts = _toList(result);
    return contacts;
  }

  Map<String, dynamic> _toMap(Contact contact) {
    final Map<String, dynamic> contactMap = Map();
    contactMap[_name] = contact.name;
    contactMap[_accountNumber] = contact.accountNumber;
    return contactMap;
  }

  List<Contact> _toList(List<Map<String, dynamic>> result) {
    final List<Contact> contacts = List.empty(growable: true);
    for (Map<String, dynamic> row in result) {
      final Contact contact = Contact(
        row[_id],
        row[_name],
        row[_accountNumber],
      );
      contacts.add(contact);
    }
    return contacts;
  }
}