Integer Encoding in Base 16384

Base16384.cs

// Encodes a positive integer (or 0) in Base 2^14, using the Unicode CJK Unified Ideographs block as digits. 
// This is a silly thing to do, but has a particular use case.
// Blog post here: http://blog.tallent.us/?p=368

public static int FromBase16384(this string value) {
	if(string.IsNullOrEmpty(value)) throw new ArgumentException();
	int letter;
	int letterBase = 1;
	int iout = 0;
	for(var x = 0; x < value.Length; x++) {
		letter = (int)value[x] - 0x4E00;
		if(letter < 0 || letter > 0x3FFF) throw new ArgumentException();
		iout += letter * letterBase;
		letterBase = letterBase << 14;
	}
	return iout;
}

public static string ToBase16384(this int value) {
	int letter;
	string result = string.Empty;
	if(value < 0) throw new ArgumentException("Negative numbers are not supported");
	do {
		letter = value % 0x4000;
		result += (char)(0x4E00 + letter);
		value = value >> 14;
	} while(value > 0);
	return result;
}