Math question: What is the smallest prime factor of the number 991?

To find the smallest prime factor of 991, we can start by testing division by primes up to the square root of 991 (which is approximately 31.5). By dividing 991 by 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, and 31, we observe that none of these primes divide evenly into 991. Therefore, we can conclude that the number 991 is a prime number itself. A prime number has only two distinct factors - 1 and the number itself. In this case, 991 has no smallest prime factor other than 991 itself.

Math Question: Given the number 991, what is the sum of its digits multiplied by the difference between its hundreds digit and tens digit?

To find the sum of the digits of 991, we add 9 + 9 + 1, which gives us 19. Now, the difference between the hundreds digit (9) and the tens digit (9) is 0. Finally, we multiply the sum of the digits (19) by the difference (0). Thus, the answer is 19 × 0 = 0.

Math Question: What is the sum of all odd numbers between 1 and 991, inclusive?

To find the sum of odd numbers, we need to first determine the number of odd terms. By figuring out the pattern, we know that the last odd number before 991 is 989 and the first odd number is 1. Using the formula n = (last term - first term)/2 + 1, we find n = (989 - 1)/2 + 1 = 495. Now, we can use the formula for the sum of an arithmetic series: S = n/2 * (first term + last term), where S represents the sum. Plugging in the values, S = 495/2 * (1 + 989) = 495/2 * 990 = 990 * 247.5 = 244,935. Therefore, the sum of all odd numbers between 1 and 991 (inclusive) is 244,935.

Max	9223372036854775807
25835	Positive integer
0b10001100	Binary number
01771452	Octal number
0x129abf	Hex number
5.012 * 10^7	Scientific notation
2^4 * 5	Factorized form
*	Random number

991 (number)

991 is an odd 3-digits prime number following 990 and preceding 992. In scientific notation, it is written as 9.91 × 10^2. The sum of its digits is 19. It has a total of 1 prime factors and 2 positive divisors. There are 990 positive integers (up to 991) that are relatively prime to 991.

Interesting facts

991 has 2 divisors, whose sum is 992
The reverse of 991 is 199
Previous prime number is 1

Basic properties

Is Prime? yes
Number parity odd
Number length 3
Sum of Digits 19
Digital Root 1

Name

Name	nine hundred ninety-one

Notation

Scientific notation	9.91 × 10^2
Engineering notation	9.91 × 10^0

Prime Factorization of 991

Prime Factorization 991

Composite number

ω	Distinct Factors	1	Total number of distinct prime factors
Ω	Total Factors	1	Total number of prime factors
rad	Radical	991	Product of the distinct prime numbers

The prime factorization of 991 is 991. Since it has a total of 1 prime factors.

Most popular turbo-numbers

4, 2, 1, 33, 688, 406, 7862, 133, 62334, 1548, 946577, 980527, 1087824, 3656297, 48407436, 8764057, 246001104, 382585747, 3132001674, 1781649768

Basic calculations (n = 991)

Multiplication

n×y

n×2	1982
n×3	2973
n×4	3964
n×5	4955

Division

n÷y

n÷2	495.5
n÷3	330.33333333333
n÷3	247.75
n÷5	198.2

Exponentiation

n^y

n²	982081
n³	973242271
n⁴	964483090561
n⁵	955802742745951

Nth Root

^y√n

²√n	31.480152477394
³√n	9.9699095472821
⁴√n	5.6107176437061
⁵√n	3.973879838931

Divisors of 991

1, 991

2 divisors

τ	Total Divisors	2	Total number of the positive divisors of n
σ	Sum of Divisors	992	Sum of all the positive divisors of n
s	Aliquot Sum	1	Sum of the proper positive divisors of n
A	Arithmetic Mean	496	Returns the sum of divisors (σ(n)) divided by the total number of divisors (τ(n))
G	Geometric Mean	31.496031496047	Returns the nth root of the product of n divisors
H	Harmonic Mean	1.9979838709677	Returns the total number of divisors (τ(n)) divided by the sum of the reciprocal of each divisors

The number 991 can be divided by 2 positive divisors. The sum of these divisors (counting 991) is 992, the average is 496.

Base conversion 991

Base	System	Value
2	Binary	1111011111
3	Ternary	1100201
4	Quaternary	33133
5	Quinary	12431
6	Senary	4331
8	Octal	1737
10	Decimal	991
12	Duodecimal	6a7
16	Hexadecimal	3df
20	Vigesimal	29b
36	Base36	rj

Cryptographic Hash Functions

md5	692f93be8c7a41525c0baf2076aecfb4
sha1	e9c535583dbe9b33c317f674d1942accca79f1b3
sha256	25b7c81e770034aeda70db74af0fb638beca992d2a535641e6313f38b9665016
sha512	d57aed1e53e945508824f1637c5facebc643fa0fc8443b528ab9edaa8e5cd89b1867e08c6f52387835f769323eaf8c2d91439e825cc4071212ab394efe531932
ripemd-160	33b8cebc66cefbf67919c7750bca67fa911f956b

991 as geometric shapes

Circle

Radius = n

Diameter	1982
Circumference	6226.636639415
Area	3085298.4548301

Sphere

Radius = n

Volume	4076707691.6489
Surface area	12341193.81932
Circumference	6226.636639415

Square

Length = n

Perimeter	3964
Area	982081
Diagonal	1401.4856403117

Cube

Length = n

Surface area	5892486
Volume	973242271
Space diagonal	1716.4623503008

Equilateral Triangle

Length = n

Perimeter	2973
Area	425253.54728701
Altitude	858.23117515038

Triangular Pyramid

Length = n

Surface area	425253.54728701
Volume	114697701.59358
Height	467.16188010391