Is there a function or value I can apply to another function to reverse the True/False value?

ISNUMBER(SEARCH(1,1)) = TRUE, but I want to know =ISNOTANUMBER(SEARCH(1,1)) = TRUE.

I'm looking for ways narrow a range a range such as using SUMIF(range1=a1,if(range2=/=number,etc))

I've tried ISTEXT, ISNONTEXT, ISNUMBER, ISERR, ISNA, but am having trouble coming up with the correct statement.