Those Fascinating Numbers 329
367 567 200 (= 25 · 33 · 52 · 7 · 11 · 13 · 17)
the
15th
colossally abundant number (see the number 55 440).
370 851 481 (=7 · 11 · 13 · 17 · 19 · 31 · 37)
the smallest pseudoprime in base 2 having seven prime factors (see the number
11 305).
378 043 979
the smallest prime number p such that p + 200 is prime and such that each
number between p and p + 200 is composite (see the number 396 733).
384 199 200
the
11th
powerful number n such that n +1 is also powerful: here 384 199 200 =
25
·
34
·
52
·
72
·
112
and 384 199 201 =
172
·
11532
(see the number 288).
387 420 490 (= 2 · 5 · 73 · 530713)
the ninth number of the form
nn
+ 1 (see the number 3 126).
391 854 937 (= 547 · 569 · 1259)
the third hyperperfect number which is the product of three distinct prime
numbers: it happens to be a 228-hyperperfect number (see the number 21).
395 096 427 (=
33
· 11 · 43 · 30937)
the number n which allows the sum
m≤n
Ω(m)=6
1
m
to exceed 1 (see the number
874 660).
402 831 360
the seventh number n such that φ(n) + σ(n) = 4n (see the number 23 760).
404 204 977
the number of ten digit prime numbers (see the number 21).
405 071 317
the value of 11 + 22 + . . . + 99 (see the number 3 413).
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