TITLE: Some lesser known open problems/ conjectures in number theory
QUESTION [6 upvotes]: What are some lesser known problems/ conjectures in number theory ( especially on prime numbers ) which have evolved in these recent years and didn't got much of attention, and obviously wasn't featured in any global mathematical mainstream , 
It includes equivalences of pre existing conjectures/ results... 
Please let me know, thanks in advance

REPLY [2 votes]: Benoit Cloitre has a paper on 10 conjectures in additive number theory, and Wikipedia also has a long list of open problems, in particular in number theory.