How to pick a switching transistor to drive LEDs? Or, how to read a transistor data sheet?
The 2N2222 might be a better choice - inexpensive, commonly available, handles the current, and overall a good choice for switching.  

The spec you want to look at most Icmax, or sometimes just Ic  (The 'C' being a subscript) which is the maximum current you'd normally be able to put through a fully turned on (saturated) transistor.

The 2N2222 apparently is popular enough to get its own web domain http://2n2222datasheet.com/  where I found several PDF spec sheets.  I see (pun not intended) that Ic is 600mA  - you could use one transistor to drive all your LEDs. 

Another spec to pay attention to is beta - the current gain.  If you're switching 400mA and the transistor has a beta of, say , 100 then you'll need to supply 400mA/100 = 4mA to the base from your digital output.  Beta isn't very consistent from transistor to transistor, even of the same type. Just make sure the math works out for the lower end of the beta range when choosing a resistor for the base.  

Practically all the other specs aren't of as much importance, not a your low 5V supply, unless you're going to drive the LEDs very fast, e.g. a few MHz.