245 (number)

245 (two hundred [and] forty-five) is the natural number following 244 and preceding 246.

In mathematics

245 is:

• a composite number.
• palindromic in bases 34 (77₃₄), 48 (55₄₈), 244 (11₂₄₄)
• a Harshad number in bases 7, 9, 11, 15, 31, 35, 36 (and 14 other bases).
• the aliquot sum of any of these numbers: 723, 1195, 2563, 3859, 9259, 10123, 12283, 14659 and 14803.
• part of the 97-aliquot tree. The aliquot sequence starting at 10222 is: 10222, 5978, 4624, 4893, 2595, 1581, 723, 245, 97, 1, 0

In online public access (library) catalogs

In the MARC format for records in online public access (library) catalogs, in which each type of information about a book (or other library material) is identified with a 3-digit number, 245 identifies the title of the item; most library catalog software requires that each record have at least a 245 tag, even if no other information is entered about the item.

In other fields

• The number of Jewish singers who returned from captivity in Babylon in c. 538 BCE following the rise of Cyrus the Great and the Persian Empire. ...besides their male and female slaves, of whom there were seven thousand three hundred thirty-seven; and they had two hundred forty-five singers, male and female. They had seven hundred thirty-six horses, two hundred forty-five mules, four hundred thirty-five camels, and six thousand seven hundred twenty donkeys. (see Nehemiah chapter 7, verses 67 to 69—Also, an almost identical reference in Ezra chapter 2, verses 65 to 67 states that there were only 200 singers, and that the slaves were "servants").
• 245T or 2,4,5-T is a common abbreviation for the widely used herbicide 2,4,5-Trichlorophenoxyacetic acid.
• "245" is the name of a jazz instrumental by Eric Dolphy, featured on his 1960 album Outward Bound.
• 245 is the international country calling code for Guinea-Bissau.