View source for 9,223,372,036,854,775,807

{{Infobox number
| number = 9223372036854775807
| factorization = 7<sup>2</sup> × 73 × 127 × 337 × 92737 × 649657
| roman = <math>\overset{ix}{MMMMMM}\quad\overset{ccxxiii}{MMMMM}\quad\overset{ccclxxii}{MMMM}\quad</math>
<math>\overset{xxxvi}{MMM}\quad\overset{dcccliv}{MM}\quad\overset{dcclxxv}{M}\quad\overset{}{DCCCVII}</math>
}}
The [[number]] '''9,223,372,036,854,775,807''' is the [[integer]] equal to 2{{sup|63}}&nbsp;−&nbsp;1.  Its [[prime factorization]] is {{nowrap|7<sup>2</sup> · 73 · 127 · 337 · 92737 · 649657}}, which is equal to {{nowrap|[[Cyclotomic polynomial|Φ]]<sub>1</sub>(2) · Φ<sub>3</sub>(2) · Φ<sub>7</sub>(2) · Φ<sub>9</sub>(2) · Φ<sub>21</sub>(2) · Φ<sub>63</sub>(2).}}

== In computing ==
The number 9,223,372,036,854,775,807, equivalent to the [[hexadecimal]] value {{nowrap|7FFF,FFFF,FFFF,FFFF{{sub|16}}}}, is the maximum value for a [[64-bit computing|64-bit]] [[integer (computer science)|signed integer]] in [[computing]]. It is therefore the maximum value for a [[variable (computer science)|variable]] declared as a [[Integer_(computer_science)#Long_integer|long integer]] ({{code|long}}, {{code|long long int}}, or {{code|bigint}}) in many programming languages running on modern computers.<ref>[https://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html "Primitive Data Types"] ''Oracle Corporation''</ref><ref>Saisang Cai, Mike B, Colin Robertson, Mike Jones, Gordon Hogenson, Billy O'Neal [https://docs.microsoft.com/en-us/cpp/cpp/integer-limits "Integer Limits"] ''Microsoft Corporation'' 28 January 2018</ref><ref>[https://db.apache.org/derby/docs/10.7/ref/rrefsqlj30435.html "BIGINT data type"] ''The Apache Software Foundation''</ref> The presence of the value may reflect an [[integer overflow]], or error.<ref> [https://www.techopedia.com/definition/14427/integer-overflow "Integer Overflow"] ''Techopedia''</ref>

This value is also the largest positive signed address offset for 64-bit CPUs utilizing [[Sign extension|sign-extended memory addressing]] (such as the [[x86-64]] architecture, which calls this "canonical form" extended addressing<ref>{{cite web|url=http://support.amd.com/TechDocs/24593.pdf|title=Volume 2: System Programming|author=AMD Corporation|date=December 2016|work=AMD64 Architecture Programmer's Manual|publisher=AMD Corporation|format=PDF|}}</ref>{{rp|page=130|date=November 2012}}). Being an odd value, its appearance may reflect an erroneous (misaligned) [[pointer (computer programming)|memory address]].

The [[C (programming language)|C]] [[C standard library|standard library]] data type <code>[[time_t]]</code>, used on operating systems such as [[Unix]], is typically implemented as either a 32- or 64-bit signed integer value, counting the number of seconds since the start of the [[Unix epoch]] (midnight UTC of 1 January 1970).<ref>[http://www.cplusplus.com/reference/ctime/time_t/ "time_t"] ''cplusplus.com''</ref> Systems employing a 32-bit type are susceptible to the [[Year 2038 problem]], so many implementations have moved to a wider 64-bit type, with a maximal value of 2{{sup|63}}−1 corresponding to a number of seconds 292 billion years from the start of [[Unix time]].

The FILETIME value used in Windows is a 64-bit value corresponding to the number of 100-nanosecond intervals since midnight UTC of 1 January 1601. The latest time that can be represented using this value is 02:48:05.4775807 UTC on 14 September 30,828 (corresponding to 9,223,372,036,854,775,807 100-nanosecond intervals since 1 January 1601).<ref>{{Cite web| last = Thulin| first = Anders| title = Interpretation of NTFS Timestamps| work = Forensic Focus| accessdate = 23 July 2019| date = 6 April 2013| url = https://articles.forensicfocus.com/2013/04/06/interpretation-of-ntfs-timestamps/}}</ref> Beyond this day, Windows will display an "invalid system time" error on startup.

Other systems encode [[system time]] as a signed 64-bit integer count of the number of ''ticks'' since some [[epoch (reference date)#Computing|epoch date]]. On some systems (such as the [[Java (programming language)|Java]] standard library), each tick is one millisecond in duration, yielding a usable time range extending 292 million years into the future.

In C#, this is available as the data type <code>long</code>.<ref>[https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/long long (C# Reference) | Microsoft Docs]</ref> The constant is available as <code>long.MaxValue</code>.
In the .NET Framework it is available as the <code>Int64</code> struct.<ref>[https://docs.microsoft.com/en-us/dotnet/api/system.int64 Int64 Struct (System) | Microsoft Docs]</ref>

The unsigned equivalent is 18,446,744,073,709,551,615, which is one more than twice this number, or 2{{sup|64}}&nbsp;−&nbsp;1.

== See also ==
* [[Magic number (programming)]]
* [[Power of two]]

==References==
{{reflist}}

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[[Category:Integers]]