What makes the number 7 a perfect number?

Posted on December 30, 2006 at 8:45 pm


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Hi Gramps,

I was just wondering what makes 7 a perfect number. It is always used to represent things and such and I know that it is used repeatedly by God, but why? Cheers!

Jake, from England


Dear Jake,

This is the mathematical definition of a perfect number. A perfect number is a number that is the sum of its divisors. The divisors of 2 are 1 and 2, which equal 3. Thus 2 is not a perfect number. The divisors of 3 are 1 and 3, which equal 4, thus three is not a perfect number. The divisors of 4 are 1, 2 and 4, which equal 7, thus four in not a perfect number. The divisors of 5 are 1 and 5, which equal 6, thus five is not a perfect number. The divisors of 6 are 1, 2 and 3, which equal six! Here, the sum of the divisors is equal to the number itself, so six is the first perfect number. If you follow this procedure, you will find that the next perfect numbers are 23, 496 and 8128.

If you were to be so laborious as to follow this process, you would find that there is only one perfect number for each set of digits; i.e., 28 is a two digit number, 496 is a three digit number, 8128 is a four digit number. The next perfect number would have five digits, and there is only one perfect number with five digits, and so on.

So seven is not really a perfect number, but it is a superstitious number. Now, as you say that the number seven is always used to represent things, what does the number seven represent? Among such things, there are seven days in a week; in certain dice games seven is the winning number; in the ancient world there were seven known ‘planetary’ bodies–the sun, moon, Mercury, Venus, Mars, Saturn and Jupiter; etc, etc.

But other numbers are also used repetitively in the scriptures. Perhaps as significant as the number seven, is the number twelve. There are twelve apostles and twelve months in the year. However, in the earlier scriptural times there were only ten months in the year. (We here take a short diversion to explain this curiosity)

The numbers seven through ten in Greek– epta, ochto, ennea, and deka– are the words from which the English words for the last four months of the year–September , October, November and December–have been derived (the year ended with the tenth month). Up until sometime before 700 B.C. the lunar period was 36 days, and so there were 36 days in each month, and ten months in a year–with five days left over. At that time there was a significant planetary disturbance which resulted in the moon being brought somewhat closer to the earth, thus shortening its orbital period from 36 days to twenty eight and a fourth days. This made the calendar rather inaccurate, and it had to be repeatedly adjusted so that the new year could begin at the winter solstice. Finally, in 46 B.C., Julius Caesar had the calendar revised to include twelve months in the year instead of ten, reflecting the moon’s current orbital period. In doing so, he changed the calendar from comprising ten months in a year to twelve months by adding two months in the middle of the year–Julius and Augustus (July and August).

The number ten is also a curiously repetitive number in history, including being the base of our common numbering system. This base was chosen because we have ten fingers, making it easy to count to ten before repeating. (Had we twelve fingers instead of ten, we would be using a duodecimal system of numbers, which would be much more efficient than the decimal system, since twelve is divisible by four numbers, while ten is divisible by only two).

So, the gist of all of the above is that there is less there than meets the eye. There is little point in trying to read mystical significance into the curious combinations of numbers or number systems. There is no scriptural information that attaches particular esoteric significance to any one number or number system over any other. Such relationships have only been generated to satisfy men’s mathematical and superstitious curiosity.

However, if you really want to have some fun with numbers, investigate “phi”, which is derived from the Fibonacci series. Better yet, investigate the fascinating Fibonacci series, which can be found at http://www.goldennumber.net.


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What makes the number 7 a perfect number? - Ask Gramps - Q and A about Mormon Doctrine
I was just wondering what makes 7 a perfect number. It is always used to represent things and such and I know that it is used repeatedly by God, but why?

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