this doesn't mean that it sounds too good to be true.
edit: fixed units - dont have easy access to micro, thanks for pointing that out.
You can spell it out, like "91 micronewtons".
You can also use exponential notation like 91e-6 N or 91x10^(-6) N.
To be fancy you can copy-and-paste unicode characters and write 91×10⁻⁶ N.
(I follow the subject by browsing news now and then at http://talk-polywell.org/ which really is about the small fusion projects. That place should have more details then at Wired.)
Use 'μ' for micro, 'm' is for milli.
this doesn't mean that it sounds too good to be true.
edit: fixed units - dont have easy access to micro, thanks for pointing that out.