| Nominal | 21818 |
| Cardinal | twenty-one thousand eight hundred eighteen |
Cardinal twenty-one thousand eight hundred eighteen | |
| Ordinal | 21,818th |
| Number of digits | 5 |
| Sum of digits | 20 |
| Product of digits | 128 |
| Number parity | Even |
| Prime factorization | 2 x 10909 |
| Prime factors | 2, 10909 |
| Number of distinct prime factors ω(n) | 2 |
| Total number of prime factors Ω(n) | 2 |
| Sum of prime factors | 10911 |
| Product of prime factors | 21818 |
| Is 21818 a prime number? | No |
| Is 21818 a semiprime number? | Yes |
| Is 21818 a Chen prime number? | No |
| Is 21818 a Mersenne prime number? | No |
| Is 21818 a Catalan number? | No |
| Is 21818 a Fibonacci number? | No |
| Is 21818 a Idoneal number? | No |
| Square of 21818 (n2) | 476025124 |
| Cube of 21818 (n3) | 10385916155432 |
| Square root of 21818 | 147.70917371646 |
| Natural Logarithm (ln) of 21818 | 9.9904905961577 |
| Decimal Logarithm (log) of 21818 | 4.3388149374176 |
| Sine of 21818 | 0.3531904767436 |
| Cosecant of 21818 | 2.8313334187829 |
| Cosine of 21818 | -0.93555143479 |
| Secant of 21818 | -1.0688883184968 |
| Tangent of 21818 | -0.37752117479556 |
| Cotangent of 21818 | -2.6488580423112 |
| The spelling of 21818 in words is "twenty-one thousand eight hundred eighteen", meaning that: |
| 21818 is not an aban number (as it contains the letter a) |
| 21818 is not an eban number (as it contains the letter e) |
| 21818 is not an iban number (as it contains the letter i) |
| 21818 is not an oban number (as it contains the letter o) |
| 21818 is not a tban number (as it contains the letter t) |
| 21818 is not an uban number (as it contains the letter u) |
| Bengali numerals | ২১৮১৮ |
| Eastern Arabic numerals | ٢١٬٨١٨ |
| Hieroglyphs numeralsused in Ancient Egypt | 𓂭𓂭𓆼𓍩𓎆𓐁 |
| Khmer numerals | ២១៨១៨ |
| Japanese numerals | 二万千八百十八 |
| Roman numerals | n/a |
| Thai numerals | ๒๑๘๑๘ |
| Arabic | واحد و عشرون ألف و ثمانية مائة و ثمانية عشر |
| Croatian | dvadeset i jedna tisuća osamsto osamnaest |
| Czech | dvacet jedna tisíc osm set osmnáct |
| Danish | en og tyve tusinde otte hundrede atten |
| Dutch | éénentwintigduizend achthonderdachttien |
| Estonian | akpe blaeve vɔ ɖekɛ alafa enyi kple wuienyi |
| Faroese | tjúgoeitt tusin og áttahundraðogátjan |
| Filipino | dalawáng pû’t isáng libó’t walóng daán at labíng-waló |
| Finnish | kaksikymmentäyksituhattakahdeksansataakahdeksantoista |
| French | vingt et un mille huit cent dix-huit |
| Greek | είκοσι μία χίλιάδες οκτακόσια δεκαοκτώ |
| German | einundzwanzigtausendachthundertachtzehn |
| Hebrew | עשרים ואחד אלף שמונה מאות ושמונה עשרה |
| Hindi | इक्कीस हज़ार आठ सौ अठारह |
| Hungarian | huszonegyezernyolcszáztizennyolc |
| Icelandic | tuttugu og eitt þúsund og áttahundrað og átján |
| Indonesian | dua puluh satu ribu delapan ratus delapan belas |
| Italian | ventunomilaottocentodiciotto |
| Japanese | 二万千八百十八 |
| Korean | 이만 천팔백십팔 |
| Latvian | divdesmit viens tūkstoši astoņsimt astoņpadsmit |
| Lithuanian | dvidešimt vienas tūkstantis aštuoni šimtai aštuoniolika |
| Norwegian | tjueett tusen åtte hundre og atten |
| Persian | بیست و یک هزار و هشتصد و هجده |
| Polish | dwadzieścia jeden tysięcy osiemset osiemnaście |
| Portuguese | vinte e um mil oitocentos e dezoito |
| Romanian | douăzeci şi una mii opt sute optsprezece |
| Russian | двадцать одна тысяча восемьсот восемнадцать |
| Serbian | двадесет и једна хиљада осамсто осамнаест |
| Slovak | dvadsaťjedna tisíc osemsto osemnásť |
| Slovene | dvaset ena tisuću osemsto asemnajst |
| Spanish | veintiún mil ochocientos dieciocho |
| Swahili | elfu ishirini na moja, mia nane na kumi na nane |
| Swedish | tjugoentusenåttahundraarton |
| Thai | สองหมื่นหนึ่งพันแปดร้อยสิบแปด |
| Turkish | yirmi bir bin sekiz yüz on sekiz |
| Ukrainian | двадцять одна тисяча вісімсот вісімнадцять |
| Vietnamese | hai mươi mốt nghìn tám trăm mười tám |
| Number 21818 reversed | 81812 | |
| Unicode Character | U+553A | 唺 |
| Unix Timestamp | Thu, 01 Jan 1970 06:03:38 +0000 | |