264 Jean-Marie De Koninck
556 160
the seventh number n such that φ(n) + σ(n) = 3n (see the number 312).
559 940
the smallest number n such that the decimal expansion of 2n contains ten
consecutive zeros, namely from the 94 170th decimal of 2n to the 94 179th (see
the number 53).
569 328
the eighth number n such that φ(n) + σ(n) = 3n (see the number 312).
570 375
the largest of the existing eight primitive non deficient numbers (see the number
945).
575 119
the smallest prime number q1 such that each number qi = 3qi−1 + 2 is prime
for i = 2, 3, . . . , 7: such a sequence of prime numbers is in some sense similar
to the Cunningham chains (see the number 1 122 659).
586 081
the number of seven digit prime numbers (see the number 21).
586 951
the smallest number n such that P (n) P (n + 1) . . . P (n + 9): here
586951 73369 21739 9467 1319 1193 1181 1091 677 29
(see the number 1 851).
590 226 (= 2 · 3 · 7 · 13 · 23 · 47)
the tenth ideal number (see the number 390).
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