Aug 20 (Reuters) - Bitcoin rose 5.01 % to $49,106.4 at 22:04 GMT on Friday, adding $2,342.1 to its previous close. Bitcoin, the world"s biggest and best-known cryptocurrency, is up 77.4% from the year"s low of $27,734 on Jan. 4. Ether , the coin linked to the ethereum blockchain network, rose 3.03% to $3,281.82 on Friday, adding $96.64 to its previous close.