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 (two hundred [and] seventeen) 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: . When written in binary, it is a non-repetitive Kaprekar number.[2] It is also the sum of all the factors of 100.

See also[edit]

  • 217, the year

References[edit]