Using strings in an enum
public enum Accounts
{
    BankOfAmerica = 123654,
    BankOfIndia = 765091
}

enum Banks
{
    BankOfFoo,
    BankOfBar,
    BankOfBlah,
    BankOfABC
}

var accounts = new Dictionary<string,string>();
accounts.Add("Bank of America", "ABC12345");
accounts.Add("Bank of India", "122-6X-666");

string number = accounts["Bank of America"];

public enum Accounts {
    BankOfAmerica,
    BankOfIndia
}

var accounts = new Dictionary<Accounts,string>();
accounts.Add(Accounts.BankOfAmerica, "ABC12345");
accounts.Add(Accounts.BankOfIndia, "122-6X-666");

string number = accounts[Accounts.BankOfAmerica];

public class BankAccount
{
    public string Name { get; set; }
    public int Number { get; set;}

    public BankAccount(string name, int number)
    {
        Name = name;
        Number = number;
    }
}

public List<BankAccount> BankAccounts = new List<BankAccount>();

public BankAccount GetAccountByName(string name)
{
    return BankAccounts.FirstOrDefault(a => a.Name == name);
}

var account = GetAccountByName("BankOfAmerica");

account.Number = 12345678;

class AccountAttribute : Attribute
{
    public string MyValue { get; set; }
    // add any other stuff...
}

public enum Accounts
{
    [Account(MyValue = "A")]
    BankOfAmerica = 123654,

    [Account(MyValue = "B")]
    BankOfIndia = 765091
}

public static class Accounts
{
    public static dynamic BankOfAmerica { get; set; }
    public static dynamic BankOfIndia { get; set; }

    static Accounts()
    {
        BankOfAmerica = 123654;
        BankOfIndia = 765091;
    }

    public static dynamic Parse(dynamic value)
    {
        if (value.ToString() == BankOfAmerica.ToString() || value.ToString() == "BankOfAmerica")
            return BankOfAmerica;
        if (value.ToString() == BankOfIndia.ToString() || value.ToString() == "BankOfIndia")
            return BankOfIndia;
        throw new Exception("cannot parse");
    }
}

Accounts.BankOfAmerica = "123";

if (account == Account.BankOfAmerica)
{
    // welcome to usa
}
else if (account == Account.BankOfIndia)
{
    // count us one by one if you can
}

try
{
    account = Account.Parse("123654");
}
catch
{
    // oops
}