296 Jean-Marie De Koninck
10 000 095
the smallest Niven number n 5 such that n+1, n+2, n+3, n+4 and n+5 are
also Niven numbers (see the number 110); it is also the smallest Niven number
n 4 such that n +1, n +2, n +3, n +4, n +5 and n +6 are also Niven numbers.
10 234 589
the smallest prime number made up of eight distinct digits (see the number
1 039).
10 708 555 (= 5 · 11 · 13 · 17 · 881)
the 10 000 000th composite number (see the number 133).
10 729 219
the fifth prime number q such that

p≤q
p is a perfect square: here
p≤10729219
p = 3672424151449 = (463 ·
4139)2
(see the number 22 073).
10 869 375
the fourth number n such that β(n)|β(n+1) and β(n+1)|β(n+2), here 67|1742
and 1742|15678 (see the number 225 504).
11 242 770
the smallest number n such that φ(n + 1) = 5φ(n); the sequence of numbers
satisfying this property begins as follows: 11 242 770, 18 673 201, 77 805 000,
117 138 840, 122 649 450, . . . (see the number 1 260).
11 243 154
the smallest number n such that ω(n) = ω(n + 1) = 6: here 11 243 154 =
2 · 3 · 13 · 17 · 61 · 139 and 11 243 155 = 5 · 7 · 11 · 19 · 29 · 53 (see the number 230).
11 309 768
the tenth powerful number n such that n +1 is also powerful: here 11 309 768 =
23
·
292
·
412
and 11 309 769 =
32
·
192
·
592
(see the number 288).
Previous Page Next Page