El Salvador is about 21 times smaller than Uzbekistan.

Uzbekistan is approximately 447,400 sq km, while El Salvador is approximately 21,041 sq km, making El Salvador 4.7% the size of Uzbekistan. Meanwhile, the population of Uzbekistan is ~31.1 million people (24.5 million fewer people live in El Salvador).
Tip: This to-scale comparison of Uzbekistan vs. El Salvador uses the Mercator projection, which distorts the size of regions near the poles.