Don’t confuse the Spreadsheet ID and the Sheet ID. They do different things!

function getSheetById(id) {
  var sheets = SpreadsheetApp.getActiveSpreadsheet().getSheets();

  return sheets.filter(function(sheet) {
    return sheet.getSheetId() === parseInt(id);
  })[0];
}

function test() {
  var sheet = getSheetById('591232091');

  Logger.log(sheet.getName());
}