JS' BigInt vs C#'s BigInteger

BigInt-Calc.cs

using System;
using System.Numerics;
using System.Diagnostics;

namespace CSBenchmark
{
    class Program
    {
        static void Main(string[] args)
        {
            var sw = Stopwatch.StartNew();
            BigInteger.Pow(new BigInteger(56), 448000);
            Console.WriteLine(sw.Elapsed);
            Console.ReadLine();
        }
    }
}

BigInt-Calc.js

const now = Date.now();
56n ** 448000n;
Date.now() - now;

BigInt-Stringify.cs

using System;
using System.Numerics;
using System.Diagnostics;

namespace CSBenchmark
{
	class Program
	{
		static BigInteger value;

		static void Main(string[] args)
		{
			value = BigInteger.Pow(new BigInteger(56), 448000);

			var sw = Stopwatch.StartNew();
			value.ToString();
			Console.WriteLine(sw.Elapsed);
			Console.ReadLine();
		}
	}
}

BigInt-Stringify.js

const n = 56n ** 448000n;
const now = Date.now();
n.toString();
Date.now() - now;