イコール  　= 　＝

等号     　    =　 ＝

不等号         =      ≠

And surprisingly:

イコール      =      ≠

And also:

イコール      =     ≒

I was really excited to finally figure out how to 変換 to ≠ because it doesn’t have a key on the keyboard, and I often want to use it. It took a little putzing around on the Wikipedia page for 等号 (とうごう), which initially told me that ≠ = 等号否定. That wouldn’t 変換 for me, so I cut off the first part and slapped that drummer with a pie that smells – 不. I have no idea why I chose that over 無 or 非; it just felt right. Attach either of those two, and the resulting word will not 変換, by the way.

※Later discovered that on Windows, = on its own can 変換 into both ≠ and ≒. And, shit, NONE of the above 変換 other than “イコール = ＝” work on Kotoeri (Apple Japanese input). So, on Kotoeri:

ノットイコール    =      ≠

There’s a big list of names here.