27
B251 is odd one out.
Factors of 16 are 1, 2, 4, 8, and 16. The only prime factor is 2. Note that 1 is neither prime nor composite number.
2 is a prime number
1 is neither a prime, nor a composite number. A prime number has only 2 factors which are 1 and itself. Composite numbers are everything else except 1 and 0. 1 and 0 are neither prime, nor composite.
0 has every number as a factor. A prime number has only 2 factors which are 1 and itself. Composite numbers are everything else except 1 and 0. 1 and 0 are neither prime, nor composite.
One
1/2
the only numbers that are neither prime nor composite are 1,0
0 has every number as a factor. A prime number has only 2 factors which are 1 and itself. Composite numbers are everything else except 1 and 0. 1 and 0 are neither prime, nor composite.
2 is a factor of 2 2, 4 and 12 are multiples of 2 31 is neither
A prime is a number with exactly two factors, itself and one. Note that 1 is neither prime nor composite, as it has exactly one factor, and that there is only one even prime, 2.
1 is neither prime nor composite.