280 (number)
From Halbeeg, the open encyclopedia · Af-Soomaali
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280 is a natural number (a regular number used in counting) that lies on the number line between 279 and 281. It is an even number (divisible by 2) and a composite number—meaning it has divisors other than 1 and itself.
In standard decimal notation, 280 is written in base-ten with three digits: 2 hundreds, 8 tens, and 0 ones. Its mathematical properties are derived mainly from its prime factorization.
Prime factorization
280 factors as 2 × 2 × 2 × 5 × 7, which can also be written as 2³ × 5 × 7. Its prime factors are therefore 2, 5, and 7. It has a total of 16 divisors, including 1, 2, 4, 5, 7, 8, 10, 14, 20, 28, 35, 40, 56, 70, 140, and 280.
Other properties
The sum of its proper divisors (1+2+4+5+7+8+10+14+20+28+35+40+56+70+140) exceeds 280 itself, making it an abundant number. Additionally, 280 is not squarefree, since 4 divides it.
General use
Like other three-digit numbers, 280 is used in historical notation (the year 280 CE and 280 BCE), measurement, and ordinary counting. The Somali word for it is "laba boqol iyo siddeetan" (two hundred and eighty).