The numbers are meaningless without context, and in context, the comparison is meaningless. External debt can be huge or tiny.
Luxembourg, population 524,853, has 2.14 trillion in external debt, or >2.7 times China's. While China's per-capita external debt is just $396, to the US's $52,170. Or how about Monaco, population 36,371, external debt, 16.5 billion.
You could add a couple more zeros by denominating the external debt in cents instead of dollars, and comparing it to student debt in dollars, and it would be exactly as useful.