Question

Number of even divisors of $1600$ is

• A. $21$
• B. $18$
• C. $3$
• D. $6$

Answer 1

Answer: (B)

$18$

Prime factorisation of $1600=2^6\times 5^2$

Number of all divisors $=(6+1)(2+1)=21$

but these divisors also include $1,5,5^2$ ie $1,5,25$ which is not even

so even divisior $=21-3=18$