As many as you like; pi is an irrational number. That means that there are no two whole numbers that you can make into a fraction exactly equal to pi. It also means that if you start to calculate pi as a decimal it never ends and never recurrs. It just goes on forever.
A few years ago two Japanese people calculated pi to eight million places of decimals, which they then published in a book. It just never ends.
* * * * *
Update: in October 2011, pi to 10 trillion (and 50) digits was published. See link.
It is an irrational number that has infinite digits.
pi = 3.141592..... ( recurs to infinity). 'pi' is an IRRATIONAL number, which means it CANNOT be converted to a RATIO(Fraction). Casually, irrational numbers are those where the decimals recur to infinity AND there is no regular order in the decimal digits. Compare pi = 3.141592.... IRRATIONAL (Irregular order of decimal digits) but 1/3 = 0.3333.... RATIONAL (Regular order of decimal digits). NB When given pi = 3.14 , 3.1416 , 22/7 , these are only APPROXIMATIONS and NOT equalities.
0 (Zero, Nil, Nought)
No. 81 is a rational number. An irrational number is a number with an endless amount of digits like pi or the square root of 2.
A decimal expansion means to write out the base 10 digits of a number. Because irrational numbers do not have a closed form, the decimal expansion will always be an approximation. Consider the irrational number pi, which has the following decimal expansion: 3.14159265... Of course there are more digits to pi than that, which is denoted by the "...". It is sadly impossible to list ALL of the digits of an irrational numbers, since if there were a finite number of digits, you could express it as a fraction, which would not be irrational.
infinite
The square root of pi is an irrational number, meaning it has an infinite number of digits after the decimal point. It is typically rounded to a limited number of digits for practical use, such as 3.1416. However, if you are looking for the actual number of digits in the square root of pi, it would be infinite.
pi is an irrational number so there are no sustained patterns in the digits of pi.
Pi is irrational, there are no last digits, the number does not end.
Currently (Sept 2014), the number of digits is 10 trillion (and fifty).
3.14
Pi is an irrational number. As such, it has an infinite number of digits.
Infinitely many. The number pi , for example, is between 1 and 1000 and, since pi is a transcendental number, it contains infinitely many digits. Plus, there are all the irrational numbers - each with infinitely many digits, and all the rationals with recurring decimals - again with infinitely many digits.
An infinite number. As of late 2011, over 10 trillion (1013) digits have been computed.
1.2411 trillion digits (1,241,100,000,000) digits of pi have been dicovered.
3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679821480865132823066470938446095505822317253594081284811174502841027019385211. This is all I can memorize. 176 digits.
These are the first 31 digits of pi:3.1415926535897932384626433832795The number not found is zero