| Nominal | 11981 |
| Cardinal | eleven thousand nine hundred eighty-one |
Cardinal eleven thousand nine hundred eighty-one | |
| Ordinal | 11,981st |
| Number of digits | 5 |
| Sum of digits | 20 |
| Product of digits | 72 |
| Number parity | Odd |
| Prime factorization | 11981 |
| Prime factors | 11981 |
| Number of distinct prime factors ω(n) | 1 |
| Total number of prime factors Ω(n) | 1 |
| Sum of prime factors | 11981 |
| Product of prime factors | 11981 |
| Is 11981 a prime number? | Yes |
| Is 11981 a semiprime number? | No |
| Is 11981 a Chen prime number? | Yes |
| Is 11981 a Mersenne prime number? | No |
| Is 11981 a Catalan number? | No |
| Is 11981 a Fibonacci number? | No |
| Is 11981 a Idoneal number? | No |
| Square of 11981 (n2) | 143544361 |
| Cube of 11981 (n3) | 1719804989141 |
| Square root of 11981 | 109.45775440781 |
| Natural Logarithm (ln) of 11981 | 9.3910773406399 |
| Decimal Logarithm (log) of 11981 | 4.0784930681666 |
| Sine of 11981 | -0.8595460696378 |
| Cosecant of 11981 | -1.1634047729651 |
| Cosine of 11981 | 0.51105826886003 |
| Secant of 11981 | 1.9567240389841 |
| Tangent of 11981 | -1.6818944570746 |
| Cotangent of 11981 | -0.59456762925503 |
| The spelling of 11981 in words is "eleven thousand nine hundred eighty-one", meaning that: |
| 11981 is not an aban number (as it contains the letter a) |
| 11981 is not an eban number (as it contains the letter e) |
| 11981 is not an iban number (as it contains the letter i) |
| 11981 is not an oban number (as it contains the letter o) |
| 11981 is not a tban number (as it contains the letter t) |
| 11981 is not an uban number (as it contains the letter u) |
| Bengali numerals | ১১৯৮১ |
| Eastern Arabic numerals | ١١٬٩٨١ |
| Hieroglyphs numeralsused in Ancient Egypt | 𓂭𓆼𓍪𓎍𓏺 |
| Khmer numerals | ១១៩៨១ |
| Japanese numerals | 一万千九百八十一 |
| Roman numerals | n/a |
| Thai numerals | ๑๑๙๘๑ |
| Arabic | إحدى عشر ألف و تسعة مائة و واحد و ثمانون |
| Croatian | jedanaest tisuća devetsto osamdeset i jedan |
| Czech | jedenáct tisíc devět set osmdesát jeden |
| Danish | elleve tusinde ni hundrede en og firs |
| Dutch | elfduizend negenhonderdéénentachtig |
| Estonian | akpe wuiɖekɛ alafa asieke blaenyi vɔ ɖekɛ |
| Faroese | ellivu tusin og níggjuhundraðogáttatiein |
| Filipino | labíng-isáng libó’t siyám na daán at walóng pû’t isá |
| Finnish | yksitoistatuhattayhdeksänsataakahdeksankymmentäyksi |
| French | onze mille neuf cent quatre-vingt-un |
| Greek | έντεκα χίλιάδες εννιακόσια ογδόντα ένα |
| German | elftausendneunhunderteinundachtzig |
| Hebrew | אחד עשר אלף תשע מאות שמונים ואחת |
| Hindi | ग्यारह हज़ार नौ सौ इक्यासी |
| Hungarian | tizenegyezerkilencszáznyolcvanegy |
| Icelandic | ellefu þúsund og níuhundrað og áttatíu og einn |
| Indonesian | sebelas ribu sembilan ratus delapan puluh satu |
| Italian | undicimilanovecentoottantuno |
| Japanese | 一万千九百八十一 |
| Korean | 만 천구백팔십일 |
| Latvian | vienpadsmit tūkstoši deviņsimt astoņdesmit viens |
| Lithuanian | vienuolika tūkstančių devyni šimtai aštuoniasdešimt vienas |
| Norwegian | elleve tusen ni hundre og åttién |
| Persian | یازده هزار و نهصد و هشتاد و یک |
| Polish | jedenaście tysięcy dziewięćset osiemdziesiąt jeden |
| Portuguese | onze mil novecentos e oitenta e um |
| Romanian | unsprezece mii nouă sute optzeci şi unu |
| Russian | одиннадцать тысяч девятьсот восемьдесят один |
| Serbian | једанаест хиљада деветсто осамдесет и један |
| Slovak | jedenásť tisíc deväťsto osemdesiatjeden |
| Slovene | enajst tisuću devetsto osemdeset ena |
| Spanish | once mil novecientos ochenta y uno |
| Swahili | elfu kumi na moja, mia tisa na themanini na moja |
| Swedish | elvatusenniohundraåttioen |
| Thai | หนึ่งหมื่นหนึ่งพันเก้าร้อยแปดสิบเอ็ด |
| Turkish | on bir bin dokuz yüz seksen bir |
| Ukrainian | одинадцять тисяч девʼятсот вісімдесят один |
| Vietnamese | mười một nghìn chín trăm tám mươi mốt |
| Number 11981 reversed | 18911 | |
| Unicode Character | U+2ECD | ⻍ |
| Unix Timestamp | Thu, 01 Jan 1970 03:19:41 +0000 | |