322 Jean-Marie De Koninck
122 522 400 (= 25 · 32 · 52 · 7 · 11 · 13 · 17)
the smallest number n such that σ(n) 5n: in this case,
σ(n)
n
5.01 (see the
number 27 720).
124 324 220
the smallest Niven number n 3 such that n + 1, n + 2, n + 3, n + 4, n + 5, n + 6
and n + 7 are also Niven numbers (see the number 110); it also is the smallest
Niven number n 2 such that n + 1, n + 2, n + 3, n + 4, n + 5, n + 6, n + 7 and
n + 8 are also Niven numbers.
125 938 261
the smallest number n such that τ (n) τ (n + 1) . . . τ (n + 11): here
4 8 8 8 8 8 8 12 12 16 16 24 (see the number 241).
129 127 041 (= 38 · 19681)
the fifth 2-hyperperfect number (see the number 21).
129 438 790
the
17th
Catalan number (see the number 14).
134 209 536 (= 213 · 3 · 43 · 127)
the second solution of
σ(n)
n
=
11
4
(see the number 47 616).
134 438 912
the
17th
dihedral perfect number (see the number 130).
137 617 728
the
20th
number n such that φ(n) + σ(n) = 3n (see the number 312).
138 200 401
the fourth prime number p such that
41p−1
1 (mod
p2)
(see the number
29).
142 990 848 (= 29 · 32 · 7 · 11 · 13 · 31)
the sixth 4-perfect number (see the number 30 240).
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