Encrypt AND Decrypt (Shift Key With Constance)

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace ConsoleApplication2

{

    class Program

    {

        static void Main(string[] args)

        {

            //Int64 id = Encrypt("abacus");

            string word=Dencrypt(1630866511392489104);

            System.Console.WriteLine(word);

            System.Console.ReadLine();

        }

        private static Int64 Encrypt(string p)

        {

            Int64 c = 31;

            for (int i = 0; i < p.Length; i++)

            {

                c = c * 47 + (byte)p[i] % 97;

            }

            return c;

        }

        private static string Dencrypt(Int64 id)

        {

            string word = "";

            while (id > 31)

            {          

                byte c= (byte) (id % 47 + 97) ; // remove the multiplied value and extract the character

                char ch= Convert.ToChar(c); // get the charactor

                word = ch + word; // create the word

                id = id / 47;

               

            }

            return word;

        }

    }

}

/*

The following Python function encrypts plain text to

cipher text. For example given the text 'abacus' the function returns a

the cypher text 334160560256. Your task is to reverse engineer the

algorithm and find the source text which results in the cypher text

15731535468486 in a language of your choosing. Remember to comment the

code with your reasoning.

def encrypt (p):

    h = 31

    for i in range(0, len(p)):

        h = h * 47 + ord(p[i]) % 97

    return h

*/