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Computer Science Level 1

True or False: $\color{#69047E}{987654321} \, \, \text{is a prime number.}$

True False

2 solutions

Sravanth C.
Feb 11, 2016

Well, I got it luckily, I just added the digits: $9+8+7+6+5+4+3+2+1=\dfrac{9\times 10}2=\boxed{45}$

And we know $45$ is divisible by $3$ and $9$ , hence $987654321$ is not a prime number.

Well Done :)

Umar Hayat - 5 years, 3 months ago

展豪張
Mar 6, 2016

$987654321=3^2\times 17^2\times 379721$