One million is a number that is represented as 1,000,000, 106, or in scientific notation, 1 × 106. It is the natural number that comes after 999,999 and before 1,000,001.
It is commonly used as a placeholder for any large number, or when someone wants to exaggerate something. For example, someone may say "I wish I had a million dollars" or "I've got a million problems today."
In the first example, a million dollars is a lot of money to most people, so when someone says that, they may not specifically mean that they want exactly 1 million dollars, just that they wish they had a lot of money.
In the second example, it is highly unlikely that the person actually has 1 million problems; they likely are just trying to communicate that they're having a very bad day. In either case, a million is being used because it is a very difficult number to conceptualize.
How big is a million?
While it isn't impossible to count to 1 million, it would require a lot of concentration, and would take a long enough time that most people probably wouldn't attempt it. If you were to count 1 number per second, it would take 1,000,000 seconds to count to 1 million. In reality, it would likely take longer than this, since it will take longer to count larger numbers. For example, 904,567 is read as "nine-hundred four thousand, five hundred and sixty-seven." That may take you more than 1 second to read, let alone keep track of while counting. However, assuming that we could do it in 1 second, 1 million seconds is still difficult to comprehend in terms of time, but we can break it down to make it easier.
Convert 1 million seconds (s) to minutes (m), hours (h), and days (d) given that there are 60 seconds in 1 minute, 60 minutes in 1 hour, and 24 hours in 1 day.
1,000,000 s ÷ 60 ≈ 16,667 m
16,667 m ÷ 60 ≈ 278 h
278 h ÷ 24 ≈ 12 d
It would take approximately 16,667 minutes, 278 hours, or 12 days to count to 1 million, assuming that we could count 1 number per second. This should put into perspective how large 1 million is. Though it is possible to count up to it, it's unlikely that you would, and even if you did, 12 days of only counting is a very long time. Now imagine how much larger a billion (1,000,000,000) and a trillion (1,000,000,000,000) are.