It is deficient: It's only proper divisors are 1, 3, and 7, which sums to 11, which is less than 21.
Answer: 2008. d(n) is number of divisors of n. I give number of divisors and list them also. The divisors of n = 2008: 1, 2, 4, 8, 251, 502, 1004, 2008 d(2008) = 8 The divisors of n = 2009: 1, 7, 41, 49, 287, 2009 d(2009) = 6
14 is deficient. It is less than the sum of it's divisors. In mathematics, a deficient number or defective number is a number n for which σ(n) < 2n. Here σ(n) is the sum-of-divisors function: the sum of all positive divisors of n, including n itself Proof.. divisors of 14 are 1,2, and 7 and 14. Now, 2n=28 and and the sum the all the divisors including 14 is 24<28
48
the divisors of 6 are: 1,2,3, and 6.
First, you want to know the definition of a perfect number: A perfect number is an integer which is equal to the sum of all its positive integer divisors that are less than itself. Example: The positive integer divisors of 6, less than 6, are 1, 2, and 3. The sum of those divisors is 1 + 2 + 3 = 6. Therefore, 6 is a perfect number. Now, 21 does not meet this definition and therefore is not a perfect number. Let's try it. There are three positive divisors of 21, namely, 1, 3, and 7, that are less than 21, itself. (There are no others.) But the sum of these divisors is 1 + 3 + 7 = 11, which is not equal to 21. Therefore, we confirm that 21 is not a perfect number.
There are 8 divisors of 105 (viz: 1, 3, 5, 7, 15, 21, 35, 105)
It is a number for which the sum of the proper divisors is less the the number. Example: 21 has divisors 1, 3, and 7. The sum is 11 which is less than 21. Note: All prime numbers are deficient and as there are an infinite number of them, there are an infinite set of deficient numbers too.
1, 2, 3, 6, 7, 14, 21, 42.
231 has 8 divisors.
Count of divisors: 12 Factorization: 3 * 3 * 7 * 11 Divisors: 1, 3, 7, 9, 11, 21, 33, 63, 77, 99, 231, 693 Sum of divisors: 1248 Number 693 is pronounced six hundred ninety three. Number 693 is a composite number. Factors of 693 are 3 * 3 * 7 * 11. Number 693 has 12 divisors: 1, 3, 7, 9, 11, 21, 33, 63, 77, 99, 231, 693. Sum of the divisors is 1248. Number 693 is not a Fibonacci number. It is not a Bell number. Number 693 is not a Catalan number.
There are eight divisors of the number 195.
The divisors of 147 are 1, 3, 7, 21, 49, 147.
The divisors of 63 are: 1, 3, 7, 9, 21, 63.
23 is a prime number. It has two divisors.
A perfect number equals the sum of its proper divisors. A deficient number is greater than the sum of its proper divisors. An abundant number is less than the sum of its proper divisors. Proper divisors of a number do not include the number itself.
The first number to have exactly 10 divisors is 48.