1089

1089 = 3 × 3 × 11 × 11

1089 = 12 × 3⁴ + 5 × 6 + 78 + 9

1089 = 987 + 65 + 4 + 32 + 1

1089 = 0^6 − 1^9 + 2^7 − 3^8 + 4^1 + 5^5 + 6^3 + 7^0 + 8^4 + 9^2

1089 = 33^2

1089 divides 100^11 - 1.

9-gonal (or enneagonal or nonagonal) numbers: a(n) = n*(7*n-5)/2, n = 18

Choose any number with 3 different digits: for example, 146
Now write this number inverted and subtract the smallest from the largest: 641−146=495

Now add this number to its inverted: 495+594=1089

Number that is the sum of 4 positive 5th powers.

Numbers k such that both k+2 and k-2 are prime.

Factors: 1, 3, 9, 11, 33, 99, 121, 363, 1089

Representations, Binary to Hexadecimal:

10001000001_2
1111100_3
101001_4
13324_5
5013_6
3114_7
2101_8
1440_9
900_11
769_12
65a_13
57b_14
4c9_15
441_16

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