Search results
Results from the WOW.Com Content Network
d() is the number of positive divisors of n, including 1 and n itself; σ() is the sum of the positive divisors of n, including 1 and n itselfs() is the sum of the proper divisors of n, including 1 but not n itself; that is, s(n) = σ(n) − n
20: It is divisible by 10, and the tens digit is even. 360: is divisible by 10, and 6 is even. The last two digits are 00, 20, 40, 60 or 80. [3] 480: 80 It is divisible by 4 and by 5. 480: it is divisible by 4 and by 5. 21: Subtracting twice the last digit from the rest gives a multiple of 21.
That is, although 360 and 2520 both have more divisors than any number twice themselves, 2520 is the lowest number divisible by both 1 to 9 and 1 to 10, whereas 360 is not the lowest number divisible by 1 to 6 (which 60 is) and is not divisible by 1 to 7 (which 420 is).
There is a leap year in every year whose number is divisible by 4, but not if the year number is divisible by 100, unless it is also divisible by 400. So although the year 2000 was a leap year, the years 1700, 1800, and 1900 were common years.
The first 15 superior highly composite numbers, 2, 6, 12, 60, 120, 360, 2520, 5040, 55440, 720720, 1441440, 4324320, 21621600, 367567200, 6983776800 (sequence A002201 in the OEIS) are also the first 15 colossally abundant numbers, which meet a similar condition based on the sum-of-divisors function rather than the number of divisors. Neither ...
F 10 (n) [5] Est. of F 10 (n) 1 9 9 2 45 45 3 150 150 4 375 375 5 750 750 6 1200 1250 7 1713 1786 8 2227 2232 9 2492 2480 10 2492 2480 11 2225 2255 12 2041 1879 13 1575 1445 14 1132 1032 15 770 688 16 571 430 17 335 253 18 180 141 19 90 74 20 44 37 21 18 17 22 12 8 23 6 3 24 3 1 25 1 1
12 (twelve) is the natural number following 11 and preceding 13.. Twelve is the 3rd superior highly composite number, [1] the 3rd colossally abundant number, [2] the 5th highly composite number, and is divisible by the numbers from 1 to 4, and 6, a large number of divisors comparatively.
360 is divisible by the number of its divisors , and it is the smallest number divisible by every natural number from 1 to 10, except 7. Furthermore, one of the divisors of 360 is 72, which is the number of primes below it. 360 is the sum of twin primes (179 + 181) and the sum of four consecutive powers of three (9 + 27 + 81 + 243).