using System;

public class Program

{

   public static void Main()

   {    

        ulong ecgi = 51681341509633;                     

        Console.WriteLine("ECGI is " + ecgi);       

        Console.WriteLine("ECGI is " + GetEcgi(GetPlmnId(ecgi), GetCellIdentity(ecgi)));        

        Console.WriteLine("ECGI is " + GetEcgi(GetPlmn(GetMcc(GetPlmnId(ecgi)),GetMnc(GetPlmnId(ecgi))), GetCellIdentity(ecgi)));

        Console.WriteLine("ECGI is " + GetEcgi(GetPlmn("200","01"), 36865));

        Console.WriteLine();

        Console.WriteLine("PLMN is " + GetPlmnId(ecgi));

        Console.WriteLine("PLMN is " + GetPlmn(GetMcc(GetPlmnId(ecgi)),GetMnc(GetPlmnId(ecgi))));       

        Console.WriteLine();

        Console.WriteLine("Cell Identity is " + GetCellIdentity(ecgi));     

        Console.WriteLine();

        Console.WriteLine("MCC is " + GetMcc(GetPlmnId(ecgi)));    

        Console.WriteLine("MCC is " + GetMcc(GetPlmn(GetMcc(GetPlmnId(ecgi)),GetMnc(GetPlmnId(ecgi)))));       

        Console.WriteLine();

        Console.WriteLine("MNC is " + GetMnc(GetPlmnId(ecgi)));

        Console.WriteLine("MNC is " + GetMnc(GetPlmn(GetMcc(GetPlmnId(ecgi)),GetMnc(GetPlmnId(ecgi)))));       

        Console.WriteLine();

   }

   static string GetMcc(uint plmn)

   {

        byte[] byteArray = BitConverter.GetBytes(plmn);                 

        return (byteArray[3] & 0x0F).ToString() + ((byteArray[3] & 0xF0) >> 4).ToString() + (byteArray[2] & 0x0F).ToString();

   }

   static string GetMnc(uint plmn)

   {

    byte[] byteArray = BitConverter.GetBytes(plmn);                

    if ((byte)((byteArray[2] & 0xF0) >> 4) == 0x0F)

        return (byteArray[1] & 0x0F).ToString() + ((byteArray[1] & 0xF0) >> 4).ToString();

    else

        return ((byteArray[2] & 0xF0) >> 4).ToString() + (byteArray[1] & 0x0F).ToString() + ((byteArray[1] & 0xF0) >> 4).ToString();

   }

   static uint GetPlmn(string Mcc, string Mnc)

   {                             

        if (Mcc.Length != 3 || Mnc.Length < 2 || Mnc.Length > 3)

                     return 0;

​

        var MccVal = Mcc.ToCharArray();

        var MncVal = Mnc.ToCharArray();                             

​

        byte[] plmn = new byte[6];

        byte[] plmnarray = new byte[4];

        plmn[0] = Convert.ToByte(MccVal[1]);

        plmn[1] = Convert.ToByte(MccVal[0]);

        plmn[2] = (MncVal.Length == 2) ? (byte)0x0F : Convert.ToByte(MncVal[0]);

        plmn[3] = Convert.ToByte(MccVal[2]);

        plmn[4] = (MncVal.Length == 2) ? Convert.ToByte(MncVal[1]) : Convert.ToByte(MncVal[2]);

        plmn[5] = (MncVal.Length == 2) ? Convert.ToByte(MncVal[0]) : Convert.ToByte(MncVal[1]);

​

        plmnarray[0] = (byte)((byte)(plmn[0] << 4) ^ (byte)(plmn[1] & 0x0F));

        plmnarray[1] = (byte)((byte)(plmn[2] << 4) ^ (byte)(plmn[3] & 0x0F));

        plmnarray[2] = (byte)((byte)(plmn[4] << 4) ^ (byte)(plmn[5] & 0x0F));

        plmnarray[3] = 0x00;                      

​

        Array.Reverse(plmnarray);

        return BitConverter.ToUInt32(plmnarray, 0);                        

   }

   public static ulong GetEcgi(uint plmn, uint cellIdentity)

   {

        return plmn * 1048576UL + cellIdentity;                  

   }

   public static uint GetCellIdentity(ulong ecgi)

   {                             

        return (uint)(ecgi % 268435456);

   }

   public static uint GetPlmnId(ulong ecgi)

   {                             

        return (uint)(256 * (ecgi / 268435456));

   }              

}

​