For Pi Day this year (2018), I will provide some results related to this interesting mathematical constant. These results are mostly inspired or taken from answers I gave at quora.com about or about similar mathematical topics.

The millionth decimal digit of π is **1** (verified with Mathematica).

The 10 millionth decimal digit of π is found to be **7**, and the 100 millionth decimal digit of π is **2**.

The billionth decimal digit of (in base 10) is **9** (verified with Mathematica).

The 2 billionth decimal digit of π is found to be **0** (this result takes a longer time to compute with Mathematica).

Here are some (repeated) number sequences or numeric strings found among the first 2 billion decimal digits of π.

The numeric string **777777777** appears at the 24, 658, 601 st decimal digit of π :

99194082457597185304**777777777**24846769425931046864

The numeric string **111111111** appears at the 812, 432, 526 th decimal digit of π :

28914504449906917135**111111111**00399876875718824885

Here are also two numeric strings from 1 to 9 in increasing order and decreasing order:

The numeric string **123456789** appears at the 523, 551, 502 nd decimal digit of π:

72604899173238892072**123456789**22486448188070486710

The numeric string **987654321** appears at the 719, 473, 323 rd decimal digit of π :

52213986632415267936**987654321**60793011913242320510

The numeric strings above can be calculated or found with the help of the following link or web page:

Irrational Numbers Search Engine

The numerical value of to 1000 decimal digits is equal to:

**36.46215960720791177099082602269212366636550840222881873870933592293407436888169990462007987570677485436814688343670070542736699139359264431565675267180230917777595737242260530320050233549595161382594571885422222305402433199779769167302876444780028452117394296018175249159350019492001619423210110480018557258718860782819839215304503453543238476218257664861595609057280314341958390400811991506636066295817900302292747422204210046403709493285441101884797707466358510710362803891181156618083260884536505255311095948029552909133361385823497120761861157606574436205295895657736468959837126404885207348833917602169536002174958035720670509318770633086434935593202425189496008880555048213388792769304015639745480898380866639428337794250284522113741878602793251848366623602214652151453276098545038540482041645516919082097210265379423765817354600472953993840487842116366153365057093066926223775915023204727672609958737278566633593210689698807508602353552267490321670730929373240451651980750157959708689483469068**

Two expressions involving π and infinite sums:

Representation of π in continued fraction form:

The sum of π and *e*, the base of natural logarithms, is equal to:

The letter* i* represents the imaginary unit of complex numbers.

Another expression involving π, *e*, and an infinite product:

And here is an identity relating the Golden Ratio, π, *e*, and the imaginary unit *i*:

The value of π can be deduced from the identity above: