using System;

public class Program

{

    public static void Main()

    {

        //Convert SOID to bytes

        var buffer = BitConverter.GetBytes(123456733333); //Enter SOID

        var bytes=Convert.ToBase64String(buffer);

        Console.WriteLine(bytes);

        //bytes (encoded) to SOID

        var newBytes = Convert.FromBase64String(bytes);

        Console.WriteLine(BitConverter.ToInt64(newBytes));  

    }

}