Wednesday, April 25, 2012
629
629 is a brilliant number (A078972). It is a semiprime whose prime factors have the same number of decimal digits.
629 is a powerful number (A007532). It can be written as a sum of positive powers of its digits: 629 = 62 + 29 + 92.
629 is 2525 in base 6. It is 275 in base 16 and 125 in base 24.
629 has two representations as a sum of two squares: 629 = 22 + 252 = 102 + 232.
629 is the hypotenuse of two primitive Pythagorean triples: 6292 = 1002 + 6212 = 4292 + 4602.
Source: On-Line Encyclopedia of Integer Sequences
Monday, April 16, 2012
527
527 is the smallest number n for which there do not exist four smaller numbers so that a1! a2! a3! a4! n! is square.
527 is 252 in base 15.
527 is a brilliant number (A078972). It is a semiprime whose prime factors have the same number of digits.
Section 527 of the U.S. Tax Code regulates soft money political campaigning.
Source: What's Special About This Number?
Wednesday, September 21, 2011
143

Monday, November 9, 2009
611
611 is a brilliant number. It is a semiprime (product of two primes) whose prime factors have the same number of decimal digits. These numbers are generally used for cryptographic purposes and for testing the performance of prime factoring programs.
611 is a number n such that n times n + 5 gives the concatenation of a number m and itself: 611 x 616 = 376376.
611 is a number with no zeroes that becomes a prime when any one digit is deleted: 61 and 11 are both primes.

For customers of some telephone companies in Canada and in the United States, 611 is the abbreviated dialing telephone number used to report a problem with telephone service, or with a payphone.
Wednesday, November 4, 2009
713

Telephone area code 713 serves the Houston area.
Source: What’s Special About This Number?