Is a Humpback whale larger then a elephant?

Definitely yes. Adult Male Sperm Whales can be as long as 20 meters. The average size is around 17 meters and they weigh 40 tonnes or more.

Adult Female Sperm whales are on an average 11 meters long and weigh around 14 tonnes.

A sperm whale is probably 10 times larger and 4 or 5 times heavier than an Elephant.