There are compounds you can buy and do-it-yourself. Ask at the local hardware store or at a home supply store like Lowe's or Home Depot for it. Look for outdoor, paintable silicone caulking suitable for masonry. It's best to get one that says it is for 25 or more years. You want it to last.
Make sure it has not rained for a few days before attempting.
Make a small bead of the caulk along the entire crack. Push it into the crack with your finger smoothing it out.
Wait a few days and then paint it, trying to blend the paint in with the older paint.
You should also consider repainting the entire house after the repairs with an elasticized paint (best water seal you can get for hurricanes!)
Once a year, give the outside of the house a good looking over to see if any small cracks have developed. Fill those using the technique above.