How many perfect numbers are there in combination of numbers made by using 4 digits.

• Answer is = 1 and that is 8128.
  They are asking about perfect numbers not perfect squares.
  Perfect Numbers are those numbers which are equal to (sum of all its factors/2).
  Like
  ( 1 + 2 + 3 + 6 ) / 2 = 6.
  The next perfect number is 28 = 1 + 2 + 4 + 7 + 14.
  This is followed by the perfect numbers 496 and 8128.
• 8 years agoHelpfull: Yes(13) No(0)
• https://en.wikipedia.org/wiki/List_of_perfect_numbers
• 8 years agoHelpfull: Yes(6) No(0)
• formulae to findout Perfect Nunmber is:
  2p−1(2p − 1) where p is prime number
  for p = 2: 21(22 − 1) = 6
  
  for p = 3: 22(23 − 1) = 28
  
  for p = 5: 24(25 − 1) = 496
  
  for p = 7: 26(27 − 1) = 8128.
• 8 years agoHelpfull: Yes(6) No(0)
• 
  
  Sorry to say this i think your answer is wrong, answer is 1 because they asked for perfect number but not perfect square number, so for finding perfect number formula is (2^(p-1))((2^p)-1) for p=1,2,3, so on.
• 8 years agoHelpfull: Yes(4) No(0)
• the first 4 digit perfect square number is 1024=32*32 and ends with
  99*99=9801
  so the total possibilities =68
  
• 8 years agoHelpfull: Yes(2) No(4)
• (2^(p-1))((2^p)-1) this is the formula for even perfect number
  so the answer if we put 4 in the place of p then answer is 120
• 8 years agoHelpfull: Yes(2) No(1)
• hii frndz...i didnt write elitmus .so dont know exactly what questions do they ask in data interpretation means related to which charts table charts pie charts bar charts or line charts...plz do help me yarr..
• 8 years agoHelpfull: Yes(1) No(1)
• perfect number is when we add the factors of that number excluding the number(number itself) then the number equals to that number eg: 6 is perfect number factors of 6 is 1,2,3,6 but we have to exclude 6 then the sum of remaining number is 1+2+3=6 and 28 is perfect number factors are 1,2,14,7,4,28 we have to exclude 28 then sum is 1+2+14+7+4=28 so the perfect number formed by four digit number is 8128
• 8 years agoHelpfull: Yes(0) No(0)