Given a number, there is an algorithm described here to find it's sum and number of factors.
Given a number, there is an algorithm described here to find it's sum and number of factors. For example, let us take the number 1225?
Answer/Solution
1767
Steps/Work
Solving for 1225=52×72
Sum of divisors = (ap+1–1)/(a–1)×(bq+1–1)/(b–1)
Here a=5, b=7 prime factors
p=2 and q=2
Sum of divisors = (53–1)/(5–1)×(73–1)/(7–1)
= (124/4)×(342/6)
= (31×57)
= 1767
Option A
Sum of divisors = (ap+1–1)/(a–1)×(bq+1–1)/(b–1)
Here a=5, b=7 prime factors
p=2 and q=2
Sum of divisors = (53–1)/(5–1)×(73–1)/(7–1)
= (124/4)×(342/6)
= (31×57)
= 1767
Option A