How many e-currency payment providers exist in the World?
Do you mean payment processors who processing credit card/check/phone payments on your sites or services such as Paypal which you can also use to send and receive money to/from anyone using your balance?
No one will let you know the exact number of E-currency payment providers because some are getting in the biz and some are leaving.
For more info you can search on google or imerchantwizard.com/db/
Thanks for your info....