Is 3.6 a prime number

Answer 1

No. The concept of prime is applicable for integers, not for fractions. This is because every non-zero fraction can go into every fraction and so when fractions are considered, there are no prime numbers.

Answer 2

No, the only even prime is 2.
36 = 2*2*3*3

A prime cannot be the product of other primes.
2 and 3 are both primes.

Answer 3

No. The whole CONCEPT of prime numbers (and composite numbers) is only defined for positive integers.

Answer 4

No.