Can't find my new tokens in my newly created smart contract

I am new to creating smart.contracts and I just created a smart contract with this source code

// contracts/ZENITHALToken.sol
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

contract ZENITHALToken is ERC20 {constructor(uint256 initialSupply) ERC20("Classic Cornerstone Zenithal", "ZENITHAL") {
_mint(msg.sender, 21000000000000000000000000);

But the contract didn't mint any tokens. Could you please explain what is wrong with the code
Thank you