Yes, the higher the number the more powerful it is. But don't be misled by the figures you read in magazines

On an engine the propellor is the brake that loads it to a certain rev. Put a smaller prop on and it loads it less so it can rev higher. Generally speaking, higher revs give more BHP but to get to the revs most engines develop their maximum BHP at you need to use a prop that's so small it's useless for flying the average model. The moral of all this is don't buy an engine simply based on how much HP the manufacturers say it makes.