217 (number)

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216 217 218
Cardinal two hundred seventeen
Ordinal 217th
(two hundred and seventeenth)
Factorization 7 × 31
Roman numeral CCXVII
Binary 110110012
Ternary 220013
Quaternary 31214
Quinary 13325
Senary 10016
Octal 3318
Duodecimal 16112
Hexadecimal D916
Vigesimal AH20
Base 36 6136

217 is the natural number following 216 and preceding 218.

217 is a centered hexagonal number, a 12-gonal number, a centered 36-gonal number, a Fermat pseudoprime to base 5, and a Blum integer.[1] It is both the sum of two positive cubes and the difference of two positive consecutive cubes in exactly one way: 217 = 6^3 + 1^3 = 9^3 - 8^3. When written in binary, it is a non-repetitive Kaprekar number.[2]

See also[edit]

  • 217, the year

References[edit]