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primitive abundant numbers
An abundant number is called primitive if none of its proper divisors is abundant.

There are infinite such numbers, both even and odd. However Dickson proved that there are only a finite number of odd primitive abundant numbers with a given number of distinct prime factors. For example, there are only 8 odd primitive abundant numbers with 3 distinct prime factors, namely, 945, 1575, 2205, 7425, 78975, 131625, 342225, and 570375.

The first primitive abundant numbers are 12, 18, 20, 30, 42, 56, 66, 70, 78, 88, 102, 104, 114, 138, 174, 186, 196 more terms

A second definition of primitive numbers excludes also those that have perfect proper divisors, like all multiples of 6. The first such numbers are 20, 70, 88, 104, 272, 304, 368, 464, 550, 572, 650, 748, 836, 945, 1184, 1312, 1376, 1430, 1504, 1575, 1696, 1870, 1888, 1952, 2002.

Primitive abundant numbers can also be... (you may click on names or numbers and on + to get more values)

ABA 18 aban 12 18 20 + 99000966 abundant 12 18 20 + 49999974 Achilles 570375 3172468 4636684 + 99198099 admirable 12 20 30 + 99999956 alternating 12 18 30 + 98989854 amenable 12 20 56 + 99999956 amicable 1184 6232 10744 + 34364912 apocalyptic 222 366 582 + 29994 arithmetic 20 30 42 + 9999942 betrothed 1575 5775 binomial 20 56 66 + 95548245 c.heptagonal 477856 1199836 2507968 + 19386368 c.nonagonal 30628 491536 575128 + 55551070 c.octagonal 342225 c.pentagonal 1266 1626 6126 + 97390806 c.triangular 2584 22144 1652176 + 96060010 cake 42 834 721928 + 5564644 Catalan 42 1430 16796 58786 congruent 20 30 56 + 9999942 constructible 12 20 30 + 393222 Cunningham 2210 3126 4095 + 95942024 Curzon 18 30 78 + 99999654 D-number 4095 16695 d-powerful 1074 1542 2205 + 9996234 de Polignac 2012985 13777785 16819275 + 96527475 decagonal 1870 3052 297297 + 77673375 dig.balanced 12 42 56 + 95510716 double fact. 945 Duffinian 1575 1660725 2553525 + 9819225 eban 30 42 56 + 66064062 economical 1184 1312 1376 + 19991936 equidigital 1184 1312 1376 + 19991936 eRAP 20 1017784 23424674 esthetic 12 56 78 + 98765454 Eulerian 66 131054 evil 12 18 20 + 99999844 fibodiv 366 5466 7806 + 44688364 Fibonacci 2584 Friedman 3378 12102 12104 + 983046 frugal 101632 102656 104704 + 81698816 gapful 550 572 1204 + 99972015 Gilda 78 364 550 3363582 Giuga 30 happy 70 368 464 + 9998574 Harshad 12 18 20 + 99967959 heptagonal 18 2205 7756 + 69292665 hexagonal 66 21945 30628 + 53804751 highly composite 12 hoax 308 364 438 + 99994614 house 78 5336 8968 6308092 iban 12 20 42 + 777774 iccanobiF 836 idoneal 12 18 30 + 102 inconsummate 272 426 438 + 999858 interprime 12 18 30 + 99994614 Jordan-Polya 12 junction 606 618 812 + 99999956 Kaprekar 999999 13641364 katadrome 20 30 42 + 76542 Leyland 368 945 2530 65792 lonely 19635 Lucas 18 lucky 1575 3465 4095 + 9999825 Lynch-Bell 12 1362 3126 + 9135 magic 87836 magnanimous 12 20 30 + 5731136 metadrome 12 18 56 + 1234578 modest 222 618 654 + 99220336 Moran 18 42 114 + 99500212 Motzkin 6536382 narcissistic 9474 nialpdrome 20 30 42 + 99999844 nonagonal 474 254475 1279575 + 66675375 nude 12 66 88 + 88828144 O'Halloran 12 20 oban 12 18 20 + 978 octagonal 5985 13736 49665 + 66797445 odious 42 56 70 + 99999956 palindromic 66 88 222 + 97922979 pancake 56 1036 2212 + 98638036 panconsummate 12 18 20 78 pandigital 78 114 894 + 95510716 partition 30 42 56 + 1741630 pentagonal 12 70 532 + 69601610 pernicious 12 18 20 + 9999856 Perrin 12 644 76725 plaindrome 12 18 56 + 55577788 power 196 15376 342225 1032256 powerful 196 15376 342225 + 99198099 practical 12 18 20 + 9989312 primorial 30 pronic 12 20 30 + 81947756 Proth 7425 49665 2392065 32743425 pseudoperfect 12 18 20 + 999999 repdigit 66 88 222 999999 repunit 364 4095 21562515 Rhonda 154462 254624 342225 + 15811444 Ruth-Aaron 78 104 2492 + 81695570 self 20 42 222 + 99999726 self-describing 14313318 14333116 15313314 + 33311514 sliding 20 70 650 Smith 438 654 762 + 99994614 sphenic 30 42 66 + 99999786 square 196 15376 342225 1032256 straight-line 222 246 258 + 999999 strobogrammatic 88 906 8968 + 99696966 super Niven 12 20 30 + 1000002 super-d 318 1036 2470 + 9999668 superabundant 12 tau 12 18 56 + 99956096 tetrahedral 20 56 364 tetranacci 56 triangular 66 78 4095 + 57571815 trimorphic 999999 uban 12 18 20 + 99000042 Ulam 18 102 114 + 9999762 undulating 272 282 464 + 89898 unprimeable 532 534 894 + 9999892 untouchable 88 246 304 + 999786 upside-down 258 654 2828 + 89491612 vampire 229648 10323225 11786350 + 45185872 wasteful 12 18 20 + 9999942 weird 70 836 4030 + 786208 Zuckerman 12 1184 1575 + 1414144 Zumkeller 12 20 30 + 99988 zygodrome 66 88 222 + 99933222