It depends on what you are going to do with the data, and how much precision you need.
Lat/long is traditionally given in degrees, minutes, and seconds, with 60 seconds to the minute, 60 minutes to the degree,and 1 degree of latitude nominally equal to 60 nautical miles (nmi). 1 minute is then 1 nmi, and 1 second is just over 100 ft.
Latitude goes from -90 to +90 degrees. Representing latitude as integer seconds gives you a range of -324000..+324000, or about 20 bits. Longitude goes -180 to +180, so representing longitude the same way requires 1 more bit.
So you can represent a complete lat/long position, to +/- 50 ft, in 41 bits.
Obviously, if you don't need that much precision, you can back down your bit count.
Observe that a traditional single-precision 32-bit float uses about 24 bits of mantissa, so you are down to about +/- 6 feet if you just convert your lat/long in seconds to float. It is kind of hard to beat two single-precision floats for this kind of thing.