143

143 = 11 x 13.

143 is the smallest brilliant number whose reversal, 341, is a different brilliant number.

143 is an aspiring number.

The last 143 digits of 143¹⁴³ form a prime number.

143 is the number of three-digit primes.

Every positive integer is the sum of at most 143 seventh powers.

143² is a divisor of 143143.

143 is the sum of three consecutive primes and the sum of seven consecutive primes: 143 = 43 + 47 + 53 = 11 + 13 + 17 + 19 + 23 + 29 + 31.

Vickers Type 143 was a British single-seat biplane designed and built in 1929.

Source: Number Gossip

611

611 = 13 x 47.

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.

Source: The On-Line Encyclopedia of Integer Sequences

713

713 = 23 x 31.

713 is a brilliant number because it is a semiprime (product of two primes) whose prime factors have the same number of decimal digits.

713 is the sum of three consecutive prime numbers: 713 = 233 + 239 + 241.

713 is the number of commutative monoids of order 7 with four idempotents. A monoid is a set that is closed under an associative binary operation and has an identity element. Unlike a group, its elements need not have inverses.

Telephone area code 713 serves the Houston area.

Source: What’s Special About This Number?