BigInteger - Cannot Instantiate Large Number - Approx 150+ Digits

Check this code, do not forget to add reference to System.Numerics to your project:

using System;
using System.Numerics;

namespace BigNumTest
{
    class Program
    {
        static void Main(string[] args)
        {
            string stringBigNum = new string('1', 160);
            BigInteger bigNum = BigInteger.Parse(stringBigNum);
        }
    }
}