197 (number)

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197 is the natural number between 196 and 198. It is also a prime number.

List of numbers — Integers << 190 191 192 193 194 195 196 197 198 199 >>
Ordinal	One hundred [and] ninety-seven
Cardinal	197th
Factorization	prime number
Roman numeral	CXCVII
Binary	11000101
Hexadecimal	C5

[edit] In mathematics

197 is a prime number and a twin prime with 199. The third of a prime quadruplet, 197 sets a record low for the Mertens function, -7. It is also a Chen prime, and an Eisenstein prime with no imaginary part.

There are two different ways of expressing 197 as a sum of consecutive primes: as the sum of the first twelve primes and also the sum of seven consecutive primes (17 + 19 + 23 + 29 + 31 + 37 + 41).

197 is a centered heptagonal number.

197 is a Keith number in base 10, because it recurs in a tribonacci-like sequence started from its digits: 1, 9, 7, 17, 33, 57, 107, 197 ...