Verify long number string IsNumber

Verify-long-number-string-IsNumber.cs

using System;
using System.Text.RegularExpressions;
using System.Linq;
using System.Numerics;
					
public class Program
{
	public static void Main()
	{
		var longNumberString = "123456789123456789123456789123456789123456789123456789123456789123456789123456789123456789123456789123456789123456789123456789123456789123456789123456789123456789123456789123456789123456789123456789";
		
		var isNumberA = int.TryParse(longNumberString, out _);
		Console.WriteLine($"isNumberA = {isNumberA}");
		
		var isNumberB = long.TryParse(longNumberString, out _);
		Console.WriteLine($"isNumberB = {isNumberB}");
		
		var isNumberC = UInt64.TryParse(longNumberString, out _);
		Console.WriteLine($"isNumberC = {isNumberC}");
		
		//Option 1: BigInteger.TryParse
		var isNumberD = BigInteger.TryParse(longNumberString, out _);
		Console.WriteLine($"isNumberD = {isNumberD}");
		
		Console.WriteLine();
		
		//Option 2: Regex
		var isNumber1 = Regex.IsMatch(longNumberString, @"^\d+$");
		Console.WriteLine($"isNumber1 = {isNumber1}");
		
		//Option 3: Linq > All with IsDigit method
		var isNumber2 = longNumberString.All(char.IsDigit);
		Console.WriteLine($"isNumber2 = {isNumber2}");
		
		
	}
}