Are platypus are mammals

Yes: specifically, it is a monotreme, which is an egg-laying mammal.

The only other species which is an egg-laying mammal is the echidna.

A platypus is a mammal because the young feed on milk produced in the mother's mammary glands. It also has fur, is warm-blooded and breathes through lungs, like other mammals.
Yes a platapus is a mamal that lays egss