Six friends Amit, Vinay, Rajiv, Mukul, Chetan and David are living on six different floors of the same building. The lowermost floor of the building is numbered 1, the floor above it is numbered 2, and so on till the topmost floor is numbered 6. No two friends live on the same floor. Vinay lives on the floor immediately above the floor on which Rajiv lives. Mukul lives on floor number 4. Amit lives on an even numbered floor. Chetan lives on floor number 1. Vinay does not live on floor number 6.

On which floor number does David live?