It's not 6v ... or it's unlikely to be 6v.
The S may be a code representing the voltage rating (but the code varies from manufacturer to manufacturer), or the 4 in "5 4" may tell you the voltage (4V). The numeric voltage ratings are somewhat standardized and the most common ones are 2.5v, 4v, 6.3v, 10v, 16v, 25v etc
Otherwise, I'm fairly sure it's a 220uF.. usually when there is enough room on the capacitor, the actual value is printed. When the cap is very small, they often use the notation where the last digit is the number of zeroes .. for example 821 means 82x10 = 820uF