What is the sum of all the divisors of 256?

What is the last digit of the sum S = 9²⁷ + 27⁹ ?

What is the median of all possible factors of 120 ?

The value of a 2-digit number is 5 times the sum of the digits. What is the product of the digits ?

Find the sum of all three-digit numbers divisible by 9.

What is the LCM of 3·6, 0·009, 0·27?