240 (number)

In mathematics

• a semiperfect number.
• a concatenation of two of its proper divisors.
• a highly composite number since it has 20 divisors total, more than any previous number.
• a refactorable number or tau number, since it has 20 divisors and 20 divides 240.
• a highly totient number, since it has 31 totient answers, more than any previous integer.
• a pronic number since it can be expressed as the product of two consecutive integers, 15 and 16.
• palindromic in bases 19, 23, 29, 39, 47 and 59.
• a Harshad number in bases 2, 3, 4, 5, 6, 7, 9, 10, 11, 13, 14, 15.
• the aliquot sum of 120 and 57121.
• part of the 12161-aliquot tree. The aliquot sequence starting at 120 is: 120, 240, 504, 1056, 1968, 3240, 7650, 14112, 32571, 27333, 12161, 1, 0.

In other fields

• A common voltage in the United Kingdom and Australia before conversion to 230 V standard.
• In pre-decimal British currency, the number of pence in a pound until 1971.
• A cholesterol level of 240 and above is considered high risk.
• The model number of the Convair 240.
• The year A.D. 240 or 240 BC.
• Datsun 240Z
• Mercedes 240D
• Nissan 240SX
• Volvo 240
• An area code overlay of the 301 area code in western Maryland.
• The famous skit by the sketch comedy group The State is entitled "$240 Worth of Pudding"
• .240 Weatherby Magnum, rifle cartridge
• 2-4-0, a Whyte notation classification of steam locomotive