Is there any nation which doesn't have any external debt? China and the US alone have a staggering 15 trillion dollars in debt. Is there any country which has no external debt and if so, then when did they pay back their debt?
The simplest answer is that yes, there are a few countries without external debt, all small.  Wikipedia has a list of the external debt of countries.  For instance Niue finished paying off its debt in October 2016.