übrigens meaning in English — by the way, for what it's worth, incidentally

English meaning

by the way adverb Used to introduce a remark that is not part of the main subject, or to add a piece of information as an aside.
for what it's worth phrase Used before an opinion or piece of information to signal that the speaker is offering it without insisting on its value or expecting it to change anything.
incidentally adverb Used to introduce a side remark, loosely connected to what was just said.

übrigens is used for these senses in English:

by the way (conjunctive, idiomatic) Incidentally; used in referencing a parenthetical statement not timely, central, or crucial to the topic at hand; foregone, passed by, something that has already happened.
for what it's worth Considering what limited worth this advice, opinion, or suggestion might have for you; used to soften the presentation of unsolicited advice or information that may not be relevant.
incidentally (speech act, conjunctive) Parenthetically, by the way.
speaking of (colloquial, disjunct) Speaking of which; relatedly, used to introduce a related topic.

adverb Used to introduce a remark that is not part of the main subject, or to add a piece of information as an aside.
adverb Used to raise something that is in fact important, while framing it casually.

nebenbei apropos Sie haben mich nicht nach meinem Rat gefragt, aber es mag keine weitere Bewandtnis haben, aber falls es Sie interessiert ich möchte mich nicht aufdrängen, aber nur nebenbei bemerkt zufällig zufälligerweise im Übrigen nebenbei gesagt da wir gerade davon sprechen