Alaska is about 1.4 times bigger than Mauritania.

Mauritania is approximately 1,030,700 sq km, while Alaska is approximately 1,481,348 sq km, making Alaska 44% larger than Mauritania. Meanwhile, the population of Mauritania is ~4.2 million people (3.5 million fewer people live in Alaska).
Tip: This to-scale comparison of Mauritania vs. Alaska uses the Mercator projection, which distorts the size of regions near the poles.