69 = 1 + 2 + 3 × 4 + 5 × 6 + 7 + 8 + 9
69 = 9 + 8 + 7 + 6 × 5 + 4 × 3 + 2 + 1
69 = 0^4 + 1^8 − 2^6 − 3^9 + 4^7 + 5^5 + 6^3 + 7^0 + 8^1 + 9^2
69 = (1 + 1 + 1) × (11 + 11 + 1)
= (22 + 2/2) × (2 + 2/2)
= 33 + 33 + 3
= 4 + (44 + 4)/4
= 55 + 5 + 5 + 5 − 5/5
= 66 + 6 × 6/(6 + 6)
= 77 − 7 − 7/7
= 88 − 8 − 88/8
= 9 × 9 − (99 + 9)/9
69 × 224612729 - 1 is Prime
Strobogrammatic number: the same upside down.
Number that is the sum of 6 positive 6th powers
Number of ordered pairs of integers (x,y) with x^2+y^2 < 5^2
Moser-de Bruijn sequence: sums of distinct powers of 4, 69 = 64 + 4 + 1 = 43 + 41 + 40
Smallest number whose sum of digits is 15.
Semiprime (Product of 2 Primes)
Semiprime s such that s-/+2 are primes.
Factors: 1, 3, 23, 69
Representations, Binary to Hexadecimal:
Result
1000101_2
2120_3
1011_4
234_5
153_6
126_7
105_8
76_9
63_11
59_12
54_13
4d_14
49_15
45_16
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Undergraduate Texts in Mathematics
Graduate Studies in Mathematics
