Palindromes and Palindromic Numbers

This morning (while thinking about what to do in case Supertyphoon Egay hits Metro Manila) I received a text message from a mathematician colleague who asked for my landline phone number. When I mentioned my phone number to him, he remarked that it is interesting because my phone number is a palindromic number. It was only then that I realized that indeed I have a palindromic phone number!

So what are palindromes and palindromic numbers?

A quick visit to Wikipedia ( http://www.wikipedia.org/ ) gave the following answers:

1. "A palindrome is a word, phrase, number or other sequence of units that has the property of reading the same in either direction (the adjustment of punctuation and spaces between words is generally permitted). The word "palindrome" was coined from Greek roots Greek πάλιν (palin) "back" and δρóμος (dromos) "way, direction" by English writer Ben Jonson in the 1600s. Composing literature in palindromes is an example of constrained writing."

(Source: http://en.wikipedia.org/wiki/Palindrome)

Examples of palindromes are the words: "rotor" and "tenet".

2. "A palindromic number is a 'symmetrical' number like 16461, that remains the same when its digits are reversed. The term palindromic is derived from palindrome, which refers to a word like rotor that remains unchanged under reversal of its letters.

Palindromic numbers receive most attention in the realm of recreational mathematics. A typical problem asks for numbers that possess a certain property and are palindromic. For instance,
the palindromic primes are 2, 3, 5, 7, 11, 101, 131, 151, … (sequence A002385 in OEIS)
the palindromic perfect squares are 0, 1, 4, 9, 121, 484, 676, 10201, 12321, …

Buckminster Fuller referred to palindromic numbers as Scheherazade numbers in his book Synergetics, because Scheherazade was the name of the story-telling wife in the 1001 Nights.

It is fairly straightforward to appreciate that in any base there are infinitely many palindromic numbers, since in any base the infinite sequence of numbers written (in that base) as 101, 1001, 10001, etc. (in which the nth number is a 1, followed by n zeros, followed by a 1) consists of palindromic numbers only."

(Source: http://en.wikipedia.org/wiki/Palindromic_number )


Now, I have a problem: Is my phone number a palindromic prime number or is it a palindromic perfect number (or both)?

Oh well, I guess having a palindromic phone number makes me special, especially on a rainy day like this :)

Cheers,

Raffy Saldana
8/17/07 in Quezon City