Math question: What is the smallest prime number greater than 1991 that can be expressed in the form 6n - 1, where n is a positive integer?

To find the smallest prime number greater than 1991 in the form 6n - 1, we start by finding the value of n. Subtracting 1 from 1991, we get 1990. Dividing 1990 by 6 gives us n = 331.6667. Since n needs to be a positive integer, we round up to the next whole number, which is 332. Substituting n = 332 into the form 6n - 1, we get 1991. Therefore, the smallest prime number greater than 1991 in the given form is 1991 itself.

Math question: If 1991 is divided by a whole number between 1 and 1991 (inclusive), what is the highest possible remainder?

To find the highest possible remainder, we need to consider the smallest divisor. The smallest divisor greater than or equal to 1 is 1 itself. When we divide 1991 by 1, the quotient is 1991 and the remainder is 0. However, if we consider all the divisors from 2 to 1991, the highest possible remainder occurs when we divide 1991 by 1991. In this case, the quotient is 1 and the remainder is also 1, which is the highest possible remainder. Thus, the answer is 1.

Math question: What is the sum of the digits of the number 1991?

The sum of the digits of the number 1991 can be found by simply adding the individual digits together. Considering 1991, we have 1 + 9 + 9 + 1 which equals 20. Therefore, the sum of the digits of 1991 is 20. The sum of digits tells us the total value obtained when all the digits of a number are added together. In this case, the number 1991 has four digits, namely 1, 9, 9, and 1. Adding these digits yields the sum of 20. Understanding the sum of digits is important as it helps in various mathematical operations, such as divisibility tests and determining whether a number is a multiple of another. It also provides valuable insights into the numerical properties of a given number. In the case of 1991, knowing that the sum of its digits is 20 aids in understanding its additive characteristics and relationships with other numbers.

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

1991 (number)

1991 is an odd 4-digits composite number following 1990 and preceding 1992. In scientific notation, it is written as 1.991 × 10^3. The sum of its digits is 20. It has a total of 2 prime factors and 4 positive divisors. There are 1800 positive integers (up to 1991) that are relatively prime to 1991.

Interesting facts

1991 has 4 divisors, whose sum is 2184
The reverse of 1991 is 1991
Previous prime number is 11

Basic properties

Is Prime? no
Number parity odd
Number length 4
Sum of Digits 20
Digital Root 2

Name

Name	one thousand nine hundred ninety-one

Notation

Scientific notation	1.991 × 10^3
Engineering notation	1.991 × 10^3

Prime Factorization of 1991

Prime Factorization 11 × 181

Composite number

ω	Distinct Factors	2	Total number of distinct prime factors
Ω	Total Factors	2	Total number of prime factors
rad	Radical	1991	Product of the distinct prime numbers

The prime factorization of 1991 is 11 × 181. Since it has a total of 2 prime factors.

Most popular turbo-numbers

10, 1, 60, 80, 239, 573, 7599, 9397, 42645, 2114, 773408, 808492, 8818529, 6801251, 91195902, 54508309, 793019219, 807962618, 954921035, 76937365

Basic calculations (n = 1991)

Multiplication

n×y

n×2	3982
n×3	5973
n×4	7964
n×5	9955

Division

n÷y

n÷2	995.5
n÷3	663.66666666667
n÷3	497.75
n÷5	398.2

Exponentiation

n^y

n²	3964081
n³	7892485271
n⁴	15713938174561
n⁵	31286450905550951

Nth Root

^y√n

²√n	44.620623034646
³√n	12.580283263893
⁴√n	6.6798669922871
⁵√n	4.5689273453983

Divisors of 1991

1, 11, 181, 1991

4 divisors

τ	Total Divisors	4	Total number of the positive divisors of n
σ	Sum of Divisors	1	Sum of all the positive divisors of n
s	Aliquot Sum	-1990	Sum of the proper positive divisors of n
A	Arithmetic Mean	0.25	Returns the sum of divisors (σ(n)) divided by the total number of divisors (τ(n))
G	Geometric Mean	1	Returns the nth root of the product of n divisors
H	Harmonic Mean	4	Returns the total number of divisors (τ(n)) divided by the sum of the reciprocal of each divisors

The number 1991 can be divided by 4 positive divisors. The sum of these divisors (counting 1991) is 1, the average is 0.25.

Base conversion 1991

Base	System	Value
2	Binary	11111000111
3	Ternary	2201202
4	Quaternary	133013
5	Quinary	30431
6	Senary	13115
8	Octal	3707
10	Decimal	1991
12	Duodecimal	119b
16	Hexadecimal	7c7
20	Vigesimal	4jb
36	Base36	1jb

Cryptographic Hash Functions

md5	96055f5b06bf9381ac43879351642cf5
sha1	643fec50e79c69bc6bbb7616afd3904acf40867c
sha256	8e9b669109df89620b94f2387dc53206a82ddc71d658f8f7a2b3a9b417370d3e
sha512	9bd8a18321feb3aac0c96f3382674b5993ad6647ced9e9141b139569434c6296a107a4fcf3b0a07561287effc139be9c24459d621f431ebdcd2ef8f93beae1ea
ripemd-160	5d6b5c0b142313bb1b70f83ce585e70c13c018a7

1991 as geometric shapes

Circle

Radius = n

Diameter	3982
Circumference	12509.821946595
Area	12453527.747835

Sphere

Radius = n

Volume	33059964994.586
Surface area	49814110.99134
Circumference	12509.821946595

Square

Length = n

Perimeter	7964
Area	3964081
Diagonal	2815.6992026848

Cube

Length = n

Surface area	23784486
Volume	7892485271
Space diagonal	3448.5131578696

Equilateral Triangle

Length = n

Perimeter	5973
Area	1716497.4243296
Altitude	1724.2565789348

Triangular Pyramid

Length = n

Surface area	1716497.4243296
Volume	930138309.25651
Height	938.56640089494