You can use the service ahrefs.com to check

Nothing would be able to tell you that. Not all backlinks are equal.

Veeeery difficult to use any link checker and get totally valid results, as mentioned above, not all links are crawled all the time and so the lists are often inaccurate. Also there's no magic number of links to guarantee "first on Google".

Quality content, which EARNS the attention of an audience will EARN links through reference and sharing. Building spammy links just to increase your backlink profile is likely to get you into a spot of bother if not straight away, when Google catches up with you. Then? It's Penguin time!

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Through competition research, you can get an idea of how much effort you have to put in to beat the competition, but you can never know how many backlinks you'll need to reach #1.

No tool can provide full data. Check using Webmaster tools