We use cookies and other tracking technologies to improve your browsing experience on our website, to show you personalized content and targeted ads, to analyze our website traffic, and to understand where our visitors are coming from. For more information, please review our cookie policy and privacy policy.
By choosing I Accept, you consent to our use of cookies and other tracking technologies.


Number 91 (ninety-one) is an odd two-digits composite number and natural number following 90 and preceding 92.

Properties of the number 91

Number of digits2
Sum of digits10
Product of digits9
Number parityOdd
Calculation was done in 0.0000319481 seconds

Prime Factorization of 91

Prime factorization7 x 13
Prime factors7, 13
Number of distinct prime factors ω(n)2
Total number of prime factors Ω(n)2
Sum of prime factors20
Product of prime factors91
Calculation was done in 0.0000078678 seconds

Divisors of 91

List of proper divisors 1, 7, 13
List of all dividers1, 7, 13, 91
Number of divisors d(n)4
Sum of all divisors σ(n)112
Aliquot sum 21
91 is a deficient number , since it is larger than the sum of its proper divisors (21). Its deficiency is 70.
Calculation was done in 0.0000200272 seconds

Prime numbers

Is 91 a prime number?No
Is 91 a semiprime number?Yes
Is 91 a Chen prime number?No
Is 91 a Mersenne prime number?No
Calculation was done in 0.0000150204 seconds


Is 91 a Catalan number?No
Is 91 a Fibonacci number?No
Is 91 a Idoneal number?No
Calculation was done in 0.0000040531 seconds

Number theory

Number theory is a branch of pure mathematics devoted primarily to the study of the integers and integer-valued functions.
91 is a Happy number
91 is not a Humble number
91 is not a Münchhausen number
91 is not a Perfect number
91 is not a Perfect square
91 is not a Palindrome
Calculation was done in 0.0019299984 seconds

Numeric Bases of 91

In mathematics, a base or radix of a numeral system is the number of unique digits, including zero, used to represent numbers in that system.
Calculation was done in 0.0000171661 seconds

Mathematical operations

Mathematical operations are actions that are performed on numbers or mathematical expressions to find a numerical result.
Square of 91 (n2)8281
Cube of 91 (n3)753571
Square root of 919.5393920141695
Natural Logarithm (ln) of 914.5108595065168
Decimal Logarithm (log) of 911.9590413923211
Calculation was done in 0.0000050068 seconds


Trigonometry is the study of the relationship between the angles and sides of a triangle.
Sine of 910.10598751175116
Cosecant of 919.4350738448116
Cosine of 91-0.9943674609282
Secant of 91-1.0056644442755
Tangent of 91-0.10658787210537
Cotangent of 91-9.3819304227354
Calculation was done in 0.0000100136 seconds

Number parity

Parity is the property of an integer of whether it is even or odd.

Is 91 an Even Number?


Is 91 an Odd Number?

Yes, the number 91 is an odd number.
Total number of all odd numbers from 1 to 91 is 46
Sum of all the odd numbers from 1 to 91 are 2116
The sum of all odd numbers is a perfect square: 2116 = 46
An odd number is any integer (a whole number) that cannot be divided by 2 evenly. Odd numbers are the opposite of even numbers.
Calculation was done in 0.0000069141 seconds

Ban number

In recreational mathematics, a ban number is a number that does not contain a particular letter when spelled out in English; in other words, the letter is "banned".
The spelling of 91 in words is "ninety-one", meaning that:
91 is an aban number (a number without the letter a)
91 is not an eban number (as it contains the letter e)
91 is not an iban number (as it contains the letter i)
91 is not an oban number (as it contains the letter o)
91 is not a tban number (as it contains the letter t)
91 is an uban number (a number without the letter u)
Calculation was done in 0.0000030994 seconds

Numeral systems

How to write 91 in other number systems?
Bengali numerals৯১
Eastern Arabic numerals٩١
Hieroglyphs numeralsused in Ancient Egypt𓎎𓏺
Khmer numerals៩១
Japanese numerals九十一
Roman numeralsXCI
Thai numerals๙๑
Calculation was done in 0.0000748634 seconds


How do you say 91 in 38 different languages?
Arabicواحد و تسعون
Croatiandevedeset i jedan
Czechdevadesát jeden
Danish en og halvfems
Estonianblaasieke vɔ ɖekɛ
Filipinosiyám na pû’t isá
Greekεννενήντα ένα
Hebrewתשעים ואחת
Icelandicníutíu og einn
Indonesiansembilan puluh satu
Latviandeviņdesmit viens
Lithuaniandevyniasdešimt vienas
Persianنود و یک
Polishdziewięćdziesiąt jeden
Portuguesenoventa e um
Romaniannouăzeci şi unu
Russianдевяносто один
Serbianдеведесет и један
Slovenedevetdeset ena
Spanish noventa y uno
Swahilitisini na moja
Turkishdoksan bir
Ukrainianдевʼяносто один
Vietnamesechín mươi mốt
Calculation was done in 0.0140709877 seconds


Number 91 reversed19
ASCII Code91[
Unicode CharacterU+005B[
Unix TimestampThu, 01 Jan 1970 00:01:31 +0000
Calculation was done in 0.0000319481 seconds
This page was generated in 0.02 seconds.