8128 and Perfect Numbers - Numberphile
For many years, 8128 was the largest known perfect number. But what is a perfect number? More links & stuff in full description below ↓↓↓ This video features Dr James Grime. James' own...
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BRADY HARAN: So we're going to talk about the number 8,128.And it's a famous type of number called perfect number.Now, this was the largest perfect number known inantiquity, or for very long time.But what is a perfect number?The smallest perfect number is the number six.So let's look at the number six.Now what does it mean?What divides into six?Well one divides into six.That's always true.Two divides into six.And three divides into six.Now, six does divide as well, but for what we're going todo, we're going to ignore the number itself.So ignore six.But if we add up the numbers that divide six--one, two, and three-- add them together, and we get thenumber six.We get the number itself.So this is a perfect number because the...
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BRADY HARAN: So we're going to talk about the number 8,128.And it's a famous type of number called perfect number.Now, this was the largest perfect number known inantiquity, or for very long time.But what is a perfect number?The smallest perfect number is the number six.So let's look at the number six.Now what does it mean?What divides into six?Well one divides into six.That's always true.Two divides into six.And three divides into six.Now, six does divide as well, but for what we're going todo, we're going to ignore the number itself.So ignore six.But if we add up the numbers that divide six--one, two, and three-- add them together, and we get thenumber six.We get the number itself.So this is a perfect number because the...
