How many legs is it biologically impossible for a centipede to have?

The story behind the answer

100. Adult centipedes always have an odd number of leg-bearing segments, so they have an odd number of leg pairs (15, 17, 19, …). One pair per segment means totals like 30, 34, 38 legs—but never 100, which would require 50 pairs (an even number of pairs). So, despite the name “centipede” (“hundred feet”), exactly 100 legs is biologically impossible.

Context tip: Centipedes are fast, predatory arthropods with one leg pair per segment; millipedes have two pairs per segment. Depending on the species, centipedes range from about 30 to well over 300 legs. Memory aid: Centipedes are “odd” hunters—odd leg pairs—so they never hit the even 50 pairs (100 legs).