1 is the factor of any nonzero natural number, and any nonzero natural number is a multiple of 1

1 is the factor of any nonzero natural number, and any nonzero natural number is a multiple of 1

No, decimals are not multiples of 1
Multiples and divisors are under the premise of integral division. Since they are integral division, there will be no numbers other than integers
1 is the factor of any nonzero natural number, and any nonzero natural number is a multiple of 1