| Nominal | 18181 |
| Cardinal | eighteen thousand one hundred eighty-one |
Cardinal eighteen thousand one hundred eighty-one | |
| Ordinal | 18,181st |
| Number of digits | 5 |
| Sum of digits | 19 |
| Product of digits | 64 |
| Number parity | Odd |
| Prime factorization | 18181 |
| Prime factors | 18181 |
| Number of distinct prime factors ω(n) | 1 |
| Total number of prime factors Ω(n) | 1 |
| Sum of prime factors | 18181 |
| Product of prime factors | 18181 |
| Is 18181 a prime number? | Yes |
| Is 18181 a semiprime number? | No |
| Is 18181 a Chen prime number? | No |
| Is 18181 a Mersenne prime number? | No |
| Is 18181 a Catalan number? | No |
| Is 18181 a Fibonacci number? | No |
| Is 18181 a Idoneal number? | No |
| Square of 18181 (n2) | 330548761 |
| Cube of 18181 (n3) | 6009707023741 |
| Square root of 18181 | 134.83693855914 |
| Natural Logarithm (ln) of 18181 | 9.8081323717193 |
| Decimal Logarithm (log) of 18181 | 4.2596177668143 |
| Sine of 18181 | -0.56737426308814 |
| Cosecant of 18181 | -1.7625050430683 |
| Cosine of 18181 | -0.82346004492337 |
| Secant of 18181 | -1.2143880036014 |
| Tangent of 18181 | 0.68901249864642 |
| Cotangent of 18181 | 1.4513524819427 |
| The spelling of 18181 in words is "eighteen thousand one hundred eighty-one", meaning that: |
| 18181 is not an aban number (as it contains the letter a) |
| 18181 is not an eban number (as it contains the letter e) |
| 18181 is not an iban number (as it contains the letter i) |
| 18181 is not an oban number (as it contains the letter o) |
| 18181 is not a tban number (as it contains the letter t) |
| 18181 is not an uban number (as it contains the letter u) |
| Bengali numerals | ১৮১৮১ |
| Eastern Arabic numerals | ١٨٬١٨١ |
| Hieroglyphs numeralsused in Ancient Egypt | 𓂭𓆼𓆼𓆼𓆼𓆼𓆼𓆼𓆼𓍢𓎍𓏺 |
| Khmer numerals | ១៨១៨១ |
| Japanese numerals | 一万八千百八十一 |
| Roman numerals | n/a |
| Thai numerals | ๑๘๑๘๑ |
| Arabic | ثمانية عشر ألف و مائة و واحد و ثمانون |
| Croatian | osamnaest tisuća sto osamdeset i jedan |
| Czech | osmnáct tisíc sto osmdesát jeden |
| Danish | atten tusinde et hundrede en og firs |
| Dutch | achttienduizend honderdéénentachtig |
| Estonian | akpe wuienyi alafa ɖeka blaenyi vɔ ɖekɛ |
| Faroese | átjan tusin og eitthundraðogáttatiein |
| Filipino | labíng-walóng libó’t isáng daán at walóng pû’t isá |
| Finnish | kahdeksantoistatuhattasatakahdeksankymmentäyksi |
| French | dix-huit mille cent quatre-vingt-un |
| Greek | δεκαοκτώ χίλιάδες εκατόν ογδόντα ένα |
| German | achtzehntausendeinhunderteinundachtzig |
| Hebrew | שמונה עשר אלף מאה שמונים ואחת |
| Hindi | अठारह हज़ार एक सौ इक्यासी |
| Hungarian | tizennyolcezerszáznyolcvanegy |
| Icelandic | átján þúsund og eitthundrað og áttatíu og einn |
| Indonesian | delapan belas ribu seratus delapan puluh satu |
| Italian | diciottomilacentoottantuno |
| Japanese | 一万八千百八十一 |
| Korean | 만 팔천백팔십일 |
| Latvian | astoņpadsmit tūkstoši simt astoņdesmit viens |
| Lithuanian | aštuoniolika tūkstančių šimtas aštuoniasdešimt vienas |
| Norwegian | atten tusen hundre og åttién |
| Persian | هجده هزار و صد و هشتاد و یک |
| Polish | osiemnaście tysięcy sto osiemdziesiąt jeden |
| Portuguese | dezoito mil cento e oitenta e um |
| Romanian | optsprezece mii una sută optzeci şi unu |
| Russian | восемнадцать тысяч сто восемьдесят один |
| Serbian | осамнаест хиљада сто осамдесет и један |
| Slovak | osemnásť tisíc jednasto osemdesiatjeden |
| Slovene | asemnajst tisuću sto osemdeset ena |
| Spanish | dieciocho mil ciento ochenta y uno |
| Swahili | elfu kumi na nane, mia moja na themanini na moja |
| Swedish | artontusenenhundraåttioen |
| Thai | หนึ่งหมื่นแปดพันหนึ่งร้อยแปดสิบเอ็ด |
| Turkish | on sekiz bin yüz seksen bir |
| Ukrainian | вісімнадцять тисяч сто вісімдесят один |
| Vietnamese | mười tám nghìn một trăm tám mươi mốt |
| Number 18181 reversed | 18181 | |
| Unicode Character | U+4705 | 䜅 |
| Unix Timestamp | Thu, 01 Jan 1970 05:03:01 +0000 | |