‵紈计
パ计羆㎝弧癬
计羆㎝ (Sum of Digits)рタ俱计计癬ㄓ 1974 计羆㎝獽琌 1 + 9 + 7 + 4 = 21
琘ㄇ计砆计羆㎝俱埃и獽嘿硂ㄇ计‵紈计 (Harshad Number)
ㄒ 3030ㄤ计羆㎝ 3 + 0 + 3 + 0 = 6τ 3030 = 6 * 505珿 3030 ‵紈计
18ㄤ计羆㎝ 1 + 8 = 9 τ 18 タ琌 9 ㄢ珿 18 ョ琌‵紈计
‵紈计程パ计厩產ガ (Dattatreya Ramachandra Kaprekar 1905-1986 ) 矗╯闽硂计厩產眔種ぇ把ゅガ计
‵紈 (Harshad) 迭方ゅ HarsaΤ尺贾ぇ種计厩產ェ冻 (Ivan M. Niven 1915-1999) ョ癸计筁瞏贝癚珿计ョ嘿ェ冻计 (Niven Number)
┏ㄇ计琌‵紈计㎡ㄢ┪‵紈计珹10, 12, 18, 20, 21, 24, 27, 30, 36, 40, 42, 45, 48, 50, 54, 60, 63, 70, 72, 80, ... (OEIS A005349)
硈尿‵紈计
‵紈计穦ぃ穦硈尿瞷㎡埃虫计材癸硈尿‵紈计 (Consecutive Harshad Numbers) 20 ㎝ 21 パ 1 9 琌‵紈计硈尿瞷琌珿и癚阶硂拜肈盽р虫计‵紈计埃贝癚埃虫计材癸硈尿 ‵紈计 110111 ㎝ 112 计厩產疭ゅ (Helen G. Grundman) 1994 靡ぃ硈尿瞷 21 ‵紈 计ㄏ琌 20 禬筁 44363342786
‵紈计籔
ㄓ‵紈计ぃぶㄤ龟┮Τ虫计琌‵紈计ㄤセō獽琌计羆㎝
иǎ‵紈计琌计 (Composite Number)硂ぃ螟瞶秆埃虫计‵紈计常穦琌计羆㎝ㄢ┪璶计羆㎝ぃ琌 1赣计礛琌计τ计羆㎝单 1 101001000... 琌计┮琌计 (Prime Number)琌‵紈计獽Τ 2357 计
计羆㎝㎝ 9 计硈闽玒冈把计猭ゅㄒ99ㄤ 计羆㎝ 18 99 ぃ琌 18 计珿 99 ぃ琌‵紈计ㄤ龟и﹚计琌 9 计笲ノ计羆㎝и璶―羆㎝ 9 计┪Ω―计羆㎝眔 9 硂氮τ獶Ω―㎝獽璸 9 ㄓ硂ョ莱ノ 3 计ぇ┮ぃ琌┮Τ 3 ┪ 9 计常琌‵紈计
‵紈计籔顶
| 顶计 | | | 计羆㎝ | | ‵紈计 |
| 1! | = 1 | = 1 | | = 1 | 琌 |
| 2! | = 1 * 2 | = 2 | | = 2 | 琌 |
| 3! | = 1 * 2 * 3 | = 6 | | = 6 | 琌 |
| 4! | = 1 * 2 * 3 * 4 | = 24 | = 2 + 4 | = 6 | 琌 |
| 5! | = 1 * 2 * 3 * 4 * 5 | = 120 | = 1 + 2 + 0 | = 3 | 琌 |
| 6! | = 1 * 2 * 3 * 4 * 5 * 6 | = 720 | = 7 + 2 + 0 | = 9 | 琌 |
| 7! | = 1 * 2 * 3 * 4 * 5 * 6 * 7 | = 5040 | = 5 + 0 + 4 + 0 | = 9 | 琌 |
| 8! | = 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 | = 40320 | = 4 + 0 + 3 + 2 + 0 | = 9 | 琌 |
| 9! | = 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9 | = 362880 | = 3 + 6 + 2 + 8 + 8 + 0 | = 27 | 琌 |
| 10! | = 1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9 * 10 | = 3628800 | = 3 + 6 + 2 + 8 + 8 + 0 + 0 | = 27 | 琌 |
итㄓ顶 (Factorial) ㄓ代刚ウ琌‵紈计挡狦琌い常琌安传‵紈计ㄤ龟硂ㄇ顶帝砛ぃ耕甧砆ㄤ羆㎝俱埃硂顶㎝‵紈计⊿Τゲ礛眖妮闽玒 432! 獽ぃ琌‵紈计 432! 玡┮Τ顶琌‵紈计
把σゅ膍の呼
Weisstein, E. W. "Harshad Number." From MathWorld. http://mathworld.wolfram.com/HarshadNumber.html.
Wikipedia. "Harshad Number." From Wikipedia. http://en.wikipedia.org/wiki/Harshad_number.
