30 (number)
From Halbeeg, the open encyclopedia · Af-Soomaali
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30 (Somali: soddon) is a natural number that falls between 29 and 31 in the sequence of integers. It is a composite number, divisible by smaller positive integers without a remainder, and therefore not a prime number.
In the base-ten numeral system, 30 consists of three tens. It commonly represents the number of days in many months of the Gregorian calendar, and is used in various measures of time, including days, minutes, and other units relating to daily life.
Mathematical properties
The divisors of 30 are 1, 2, 3, 5, 6, 10, 15, and 30. It is the product of the three smallest prime numbers: 2 × 3 × 5. The sum of its proper divisors (1+2+3+5+6+10+15 = 42) exceeds 30 itself, which makes it an abundant number.
30 is also the sum of the squares of the first four positive integers: 1² + 2² + 3² + 4² = 30. For this reason, it belongs to the class of square pyramidal numbers.
Common uses
In the Gregorian calendar, April, June, September, and November each have 30 days. In time measurement, 30 minutes equals half an hour. In educational and employment systems, periods of 30 days are commonly used for calculating payments and contract terms.
In various languages, the number is called: Arabic 30 (ثلاثون), English thirty, French trente, Italian trenta, Turkish otuz. In Somali, soddon belongs to the base-ten counting system positioned between twenty and forty.