| Deficient Number |
Website Links For Number |
Information AboutDeficient Number |
| CATEGORIES ABOUT DEFICIENT NUMBER | |
| integer sequences | |
|
The first few deficient numbers are: : 1 , 2 , 3 , 4 , 5 , 7 , 8 , 9 , 10 , 11 , 13 , 14 , 15 , 16 , 17 , 19 , 21 , 22 , 23 , 25 , 26 , 27 , … As an example, consider the number 21. Its divisors are 1, 3, 7 and 21, whose sum is 32. Because 32 is less than 2 × 21, the number 21 is deficient. Its deficiency is 2 × 21 − 32 = 10. An infinite number of both Even And Odd deficient numbers exist. For example, all Prime Number s, all prime powers and all proper Divisor s of deficient or Perfect Number s are deficient. Closely related to deficient numbers are Perfect Number s with ''σ''(''n'') = 2''n'', and Abundant Number s with ''σ''(''n'') > 2''n''. The Natural Number s were first classified as either deficient, perfect or abundant by Nicomachus in his ''Introductio Arithmetica'' (circa 100 ). SEE ALSO EXTERNAL LINKS |
|
|