Numbers: 28

Today is the 28th of October. Mathematically, 28 is a perfect number, equal to the sum of its divisors: 1 + 2 + 4 + 7 + 14 = 28. The first four perfect numbers are 6, 28, 496 and 8,128, but some ancient religions consider 28 to be the most perfect of all, as it is the number of letters in the Arabic and Phoenician alphabets. It is also: The number of days in three out of four Februaries.

The number of dominoes in a standard set.

The value, in millions of pounds, of the seven Picasso paintings stolen this week.

The top speed of a lone lobster in centimetres per second.

The number of people per square kilometre in the United States.

The name of the parakeet which is also known as the yellow-collared parakeet of Australia, whose cry is said to sound like '28'.

COMPETITION: There were so many correct entries to our last '26 L of the A' (letters of the alphabet) competition, we have decided to concoct a more testing set. There will be three prizes of The Larousse Dictionary of Literary Characters ('From Chaucer to Chandler, Austen to Alice Walker') for the best attempts at the following.

5 N (GFD).

2504 N of T (28 O) I.

2 G of V 5 FTTOZ 3 LM from S (the M) Send your entries to: Pastimes, The Independent, 40 City Road, London EC1Y 2DB, to arrive by the morning of 3 November.

Results and winners from last week: The longest word-chain submitted was of 11 letters: Austringers, austringer, astringer, stringer, stinger, singer, singe, sing, sin, in, I. The first three words - all in Chambers - mean 'keepers of goshawks'.

In view of our stated preference for words in common usage, we have treated this on a par with: Strapping(s), splitting(s), startling(s) and other 9-10 letter entries. Copies of Chambers Encyclopaedic Dictionary go to: Andrew Cook (Abingdon), Tony Kilburn (Winkleigh) and Iona Douglas (Oxford).

'The Anaesthetist'