Because the property of being a prime or composite is defined only for numbers which are two or larger. If 1 were considered a prime then the fundamental theorem of arithmetic - the unique prime factorisation theorem - would fail.
It is 1 that is neither a prime or a composite number The number 1 is neither prime nor composite.
The number 1 is neither a prime nor a composite number.
1 and 0 are neither composite or prime numbers
1 is not considered to be a prime or a composite number
0 and 1 are neither prime nor composite.
The number '1' is neither prime nor composite.
19 is prime the only numebr that is neither prime or composite is 1
1 is neither prime nor composite.
the number 1 is neither. it is a special number. prime, nor composite.
No 1 is neither a prime number or a composite number
Identify each number as prime, composite or neither: 1
Neither