The number 70 (seventy) is a significant integer, primarily known in mathematics as the smallest weird number—an abundant number that is not semi-perfect. Here are key details regarding the number 70:
Definition: It is the natural number following 69 and preceding 71. It is a composite number, with its proper divisors being 1, 2, 5, 7, 10, 14, and 35.
“Weird Number” Status: The sum of 70’s proper divisors is 1+2+5+7+10+14+35 = 74. Because 74 > 70, it is considered an abundant number. However, no subset of these divisors adds up to exactly 70, making it “weird”.
Mathematics: 70 is a primitive abundant number, a Pell number, and a central binomial coefficient. Representation: In Roman numerals, 70 is written as LXX.
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