The insect that has hundred legs is the centipede.
However in reality the centipede does not really have 100 legs although the name implies it does and it's a common though that the centipede has a 100 legs.
There's really no insect including centipedes that actually have 100 legs.
Centipedes are also in reality classified as myriapods and not insects and can have anywhere from as little as 15 legs to 191 pairs of legs, but not always an odd number of pairs of legs.
Millipedes are another group of myriapods which also don't have 100 legs, although some species of Millipedes have been found with over 1,300 legs.
The name centipede is also a bit misleading, and while they are known for having many legs, the number of legs varies greatly by species and they always have an odd number of leg pairs.
Millipedes have two pairs of legs per body segment and while some Millipedes have been discovered with over 1,000 legs, the name is not literal.
And insects are also a different group of arthropods, typically also have 3 pairs of legs.