70

70 = 2 × 5 × 7

70 = 1² + 34 + 5 + 6 + 7 + 8 + 9

70 = 9 + 8 + 7 + (6 + 5 + 4 × 3) × 2 × 1

70 = 0^8 − 1^9 + 2^4 + 3^5 − 4^7 + 5^6 + 6^0 + 7^2 + 8^3 + 9^1

70 = 3^2 + 5^2 + 6^2

a(n) = 2^n + n, n = 6

smallest integer with the sum of its divisors ( 1 , 2 , 5 , 7 , 10 , 14 , 35) larger than then number itself.

836 is the next such number

1² + 2² + 3² + ... + 24² = 70²

70 = (8,4) = 8 × 7 × 6 × 5/24.

Weird number: abundant but not pseudoperfect

70 = binomial(5 + 3, 4) is the 5th pentatope number.

Sphenic number: Product of 3 distinct Primes, (List)

Number n such that (n^97+1)/(n+1) is prime.

Number of intersection points of semicircles joining all pairs of 8 equally spaced points along a line

Factors: 1, 2, 5, 7, 10, 14, 35, 70

Seventy

Representations, Binary to Hexadecimal:

1000110_2
2121_3
1012_4
240_5
154_6
130_7
106_8
77_9
64_11
5a_12
55_13
50_14
4a_15
46_16

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