The two characters on the top are not Korean (as Got_4by4 suggested), but indeed Chinese. It's a number written in ancient Chinese text. Probably it says "twenty", but I am not quite sure. The first character is in an obsolete (or local)form that is no longer in use anywhere.
The really interesting part is the characters on its back. "大宋宣和二年" (Da Song Xuan He Er Nian), or literally "The 2nd Year of Xuan-He Period, Song Dynasty". What year is that? Well, as a mandarin translator let me translate it into modern and plain English for you - it's A.D. 1120!
This silver ingot was made about 9 centuries ago! A true treasure with great value, if it's not a modern replica...