Hi Puru,
If you don't need the currency symbol, then dont give the [Type] property.
Only the [Culture] property is enough to get the digits in required format.
<telerik:RadNumericTextBox RenderMode="Lightweight" runat="server" ID="radtxtAmt" Width="200px" EmptyMessage="Enter unit price" MinValue="0" Culture="en-US"></telerik:RadNumericTextBox>
OR,
u can even set the Culture property from code behind like below
radtxtAmt.Culture = CultureInfo.CreateSpecificCulture("en-US");
Hope this helps :)
Regards,
KK