1240

1240 is a year in the 13th century as well as a natural number. In the Julian calendar, 1240 was a leap year, having 366 days. It sits in the early part of the 1240s decade.

Historically, 1240 is notable for the Mongol invasion of Rus'. During the campaigns of Batu Khan, Kiev was captured in December 1240, marking a turning point in the region. The campaign also damaged or destroyed several other Rus' towns, contributing to the decline of the traditional Kievan political center and the rise of new regional powers under Mongol influence.

As a number, 1240 has a straightforward arithmetic profile. It factors as 2^3 × 5 × 31, making it an even, composite number with 16 positive divisors. Examples include 1, 2, 4, 5, 8, 10, 20, 31, 40, 62, 124, 155, 248, 310, 620, and 1240. The Roman numeral representation is MCCXL. In binary it is 10011011000, and in hexadecimal it is 0x4D8.

In summary, 1240 serves as both a historical reference point in the Mongol expansion into Eastern Europe and a compact example of a composite, even integer with multiple divisors in the realm of number theory.