riddle

[Don Shepherd]

if you had Social Security number 223-09-2870, would you be special, and if yes, why?

(for the record, I have no idea if this Social Security number exists, but if it does I would like to have it, but then everyone would know it, so maybe that's not such a good idea)

[Joe Horn]

(12-11-2018 01:41 PM)Don Shepherd Wrote:  if you had Social Security number 223-09-2870, would you be special, and if yes, why?

(for the record, I have no idea if this Social Security number exists, but if it does I would like to have it, but then everyone would know it, so maybe that's not such a good idea)

Yes, you would be special, because it would mean that you were the only person to receive that particular SSN. It would also mean that you were from Virginia, and were born on 18 August 1907, and died August 1985, and had the name Clarence Robertson. (See the very first hit when that SSN is typed into Google).

[Don Shepherd]

(12-11-2018 04:32 PM)Joe Horn Wrote:  

(12-11-2018 01:41 PM)Don Shepherd Wrote:  if you had Social Security number 223-09-2870, would you be special, and if yes, why?

(for the record, I have no idea if this Social Security number exists, but if it does I would like to have it, but then everyone would know it, so maybe that's not such a good idea)

Yes, you would be special, because it would mean that you were the only person to receive that particular SSN. It would also mean that you were from Virginia, and were born on 18 August 1907, and died August 1985, and had the name Clarence Robertson. (See the very first hit when that SSN is typed into Google).

I'd bet that old Clarence never recognized the mathematical significance of his number.

[Albert Chan]

(12-11-2018 04:32 PM)Joe Horn Wrote:  Yes, you would be special, because it would mean that you were the only person to receive that particular SSN. It would also mean that you were from Virginia, and were born on 18 August 1907, and died August 1985, and had the name Clarence Robertson. (See the very first hit when that SSN is typed into Google).

223092870 = 2·3·5·7·11·13·17·19·23

I believe all SS# are unique (at least for now ...)
Just because above SS# related to a real person does not make it special.

[Don Shepherd]

(12-11-2018 05:28 PM)Albert Chan Wrote:  

(12-11-2018 04:32 PM)Joe Horn Wrote:  Yes, you would be special, because it would mean that you were the only person to receive that particular SSN. It would also mean that you were from Virginia, and were born on 18 August 1907, and died August 1985, and had the name Clarence Robertson. (See the very first hit when that SSN is typed into Google).

223092870 = 2·3·5·7·11·13·17·19·23

I believe all SS# are unique (at least for now ...)
Just because above SS# related to a real person does not make it special.

Correct Albert. The product of the first 223092870 primes, from 223092870 to 223092870, containing a 223092870 perfect number and my age 223092870 in 2 years.

The beauty of math!

[Albert Chan]

223092870 = 2·3·5·7·11·13·17·19·23

This SS# had huge number of factors = 2^9 = 512

For valid SS# (i.e. 9 digits limits), what number have most factors ?

Edit: these 9-digits numbers have maximum of 1344 factors
http://math.univ-lyon1.fr/~nicolas/ramanujanNR.pdf, page 152

735134400 = 2^6 * 3^3 * 5^2 * 7 * 11 * 13 * 17
821620800 = 2^6 * 3^3 * 5^2 * 7 * 11 * 13 * 19
931170240 = 2^6 * 3^2 * 5 * 7 * 11 * 13 * 17 * 19
994593600 = 2^6 * 3^3 * 5^2 * 7 * 11 * 13 * 23

[Don Shepherd]

(12-11-2018 06:00 PM)Albert Chan Wrote:  223092870 = 2·3·5·7·11·13·17·19·23

This SS# had huge number of factors = 2^9 = 512

For valid SS# (i.e. 9 digits limits), what number have most factors ?

Edit: these 9-digits numbers have maximum of 1344 factors
http://math.univ-lyon1.fr/~nicolas/ramanujanNR.pdf, page 152

735134400 = 2^6 * 3^3 * 5^2 * 7 * 11 * 13 * 17
821620800 = 2^6 * 3^3 * 5^2 * 7 * 11 * 13 * 19
931170240 = 2^6 * 3^2 * 5 * 7 * 11 * 13 * 17 * 19
994593600 = 2^6 * 3^3 * 5^2 * 7 * 11 * 13 * 23

Albert, thanks for that reference. Very interesting.

I have a program on my 12c+ that can verify the number of factors pretty quickly.

[Joe Horn]

(12-11-2018 05:28 PM)Albert Chan Wrote:  I believe all SS# are unique (at least for now ...)
Just because above SS# related to a real person does not make it special.

Sorry for not specifying that I was using American English, in which "special" can be a synonym for "unique", according to dictionary.com and the Random House Unabridged English Dictionary (which dictionary.com is based on):