Senegal is about 1,385 times bigger than Wallis and Futuna.

Wallis and Futuna is approximately 142 sq km, while Senegal is approximately 196,722 sq km, making Senegal 138,437% larger than Wallis and Futuna. Meanwhile, the population of Wallis and Futuna is ~15,891 people (17.9 million more people live in Senegal).
Tip: This to-scale comparison of Wallis and Futuna vs. Senegal uses the Mercator projection, which distorts the size of regions near the poles.