178 Jean-Marie De Koninck
8 208
one of the four numbers which can be written as the sum of the fourth powers
of its digits: 8 208 = 84 + 24 + 04 + 84; the others are 1, 1 634 and 9 474.
8 241
the number of Carmichael numbers
1012
(Jaeschke, 1990); see the number
646.
8 363
the number of five digit prime numbers (see the number 21).
8 408
the smallest number n such that π(n) = n/8 (see the number 330).
8 450
the only solution n
1012
of σ(n) = 2n + 119.
8 467
the
32nd
Lucas prime number (see the number 613).
8 521
the eighth prime number of the form
(x4
+
y4)/2
(see the number 41): here
8 521 =
(74
+
114)/2.
8 539
the smallest prime number q such that

p≤q
p is divisible by 2 310 (= 2 · 3 · 5 ·
7 · 11): here this sum is equal to 4 218 060 (see the number 269).
8 549 (= 83 · 103)
the third Canada perfect number: 82 + 52 + 42 + 92 = 83 + 103 (see the number
125).
8 575
the second composite number n such that σ(n + 2) σ(n) = 2 (see the number
434).
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