CREATOR: @the_accountant

Twenty-eight

Historical Significance: 28 (twenty-eight) is the natural number following 27 and preceding 29. In mathematics It is a composite number, its proper divisors being 1, 2, 4, 7, and 14. Twenty-eight is the second perfect number - it's the sum of its divisors: 1+2+4+7+14. As a perfect number, it is related to the Mersenne prime 7, since 2(3 − 1)(23 − 1) = 28. The next perfect number is 496, the previous being 6. Twenty-eight is the sum of the totient function for the first nine integers. Since the greatest prime factor of 282 + 1 = 785 is 157, which is more than 28 twice, 28 is a Størmer number. Twenty-eight is a harmonic divisor number, a happy number, a triangular number, a hexagonal number, and a centered nonagonal number. In science • The atomic mass of silicon. • The atomic number of nickel. • The fourth magic number in physics. • The curing time of concrete is classically considered 28 days. Astronomy • The rotation time of the surface of the Sun varies due to it being gas and plasma. At 45°, it rotates every 28 days. • The Sun's gravity is 28 times that of Earth. • Messier object M28, a magnitude 8.5 globular cluster in the constellation Sagittarius. 28 is also: • The number of Hebrew letters in Genesis 1:1, the first verse of the Bible. • The number of wheels on a Lockheed C-5 Galaxy. This hand drawn (with mouse) using sophisticated software (paint) was created as an exclusive NFT by The Accountant. Collection: The Numbers Use Case: Good for Counting Rarity: Common Minted on July 3, 2021 during the first week of Enter.art