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Really Big Stars

Here is a compilation and comparison of some of the largest know stars.
1 solar radius is the radius of our sun, so a star with 3 solar radii would be 3 times bigger than our sun.
But we want bigger numbers that that.
Some stars change in size and for the more distant stars, we simply can't be sure of an exact size.
The Sun
Solar Radius:- 1
Our home star, our planet Earth would fit into it 1.3 million times. (1,300,000)

VV Cephei B
Solar radii:- 10
That would fit 13 million Earths.

Solar radii:- 35.4
This is one of the most massive stars, (as in the weight kind of massive, the most 'stuff') and also one of the brightest. (That we know of.)

Solar radii:- 44.2

Solar radii:- 78

Peony Nebula Star
Solar radii:- 100
A candidate for the brightest star in our Galaxy.

La Superba
Solar radii:- 215
One of the 'coldest' know stars.

Mira A 
Solar radii:- 400

CE Tauri
Solar radii:- 608
That's 790,400,000 Earths!

RS Persei
Solar radii:- 1,000
1,000 times our sun.
1,300,000,000 Earths. (1.3 billion)
100 times the size of VV Cephei B.

S Persei
Solar radii:- 780 to 1,230
Thats 0.78 to 1.23 of  RS Persei, both are in the Persei double cluster.
1,014,000,000 to 1,599,000,000 Earths.

Mu Cephei
 Solar Radii:- 650-1,420

RW Cephei
Solar Radii:-1,260–1,610
That's a maximum of 2,093,000,000 Earths. 

VY Canis Majoris
Solar Radii:- 1,420
Originally predicted to be around 1,800 to 2,100 radii, which broke the laws of stellar evolutionary theory, more recently this has been remeasured and brought down to size. 

VX Sagittarii
Solar radii:- 1,520

UY Scuti
Solar radii:- 1,708 ( ±192)
The biggest star we've found. 
That would be a maximum of 2,470,000,000 Earths.
On earth, as of 22/10/2013, according to Wikipedia there are  7,119,000,000 billion people on Earth. 
With the amount of Earths that would fit into UY Scuti, there'd be 17,583,930,000,000,000,000, or, seventeen quintillion, five hundred and three quadrillion and nine hundred and thirty trillion people.

Now, "The average weight of human varies depending on the sex of the person, for instance the weight of women is between 54 and 64 kg. On the other hand, men will have an average weight between 76 and 83 kg."[ref] So an overall average is a mass of 69.25 kg. so the total average mass of 17,583,930,000,000,000,000 people is 1,217,687,152,500,000,000,000 kg.
Or, 1,217,687,152,500,000,000 metric tonnes of people. That's 0.0000127213451% of the Earth's mass. 

UY Scuti has 32 solar masses, one of which is 1,988,550,000,000,000,000,000,000,000 tonnes.
So a total of 63,633,600,000,000,000,000,000,000,000,000 tonnes.
So all those people equate to 0.000000000001914% of the mass of the star they'd occupy.