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Properties of the Number 21730

Twenty-One Thousand Seven Hundred Thirty

Basics

Value: 21729 → 21730 → 21731

Parity: even

Prime: No

Previous Prime: 21727

Next Prime: 21737

Digit Sum: 13

Digital Root: 4

Palindrome: No

Factorization: 2 × 5 × 41 × 53

Divisors: 1, 2, 5, 10, 41, 53, 82, 106, 205, 265

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010011100010

Octal: 52342

Duodecimal: 106AA

Hexadecimal: 54e2

Square: 472192900

Square Root: 147.41099009232656

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: No

Perfect Number: No

Special

Kaprekar Constant: No

Munchausen Constant: No

Armstrong Number: No

Kaprekar Number: No

Catalan Number: No

Vampire Number: No

Taxicab Number: No

Super Prime: No

Friedman Number: No

Fermat Number: No

Cullen Number: No

OEIS Sequences

a(n) = 4·a(n-1) - a(n-2) - 4, with a(0) = 2, a(1) = 4. A71954
Expansion of e.g.f. ∑k>=1 log(1 + x)k / (k * (1 - log(1 + x)k)). A330354
T(n,k) = Number of n X k 0..1 arrays with every element equal to 0, 2, 3, 4, 6 or 7 king-move adjacent elements, with upper left element zero. A299221
a(n) = n·A002088(n). A143270
Sum of sums of omegas of the parts over all strict integer partitions of n. A325515
Triangle of coefficients of polynomials v(n,x) jointly generated with A210858; see the Formula section. A210859
Numbers k that are the product of four distinct primes such that x2+y2 = k has integer solutions. A248712
a(n) = 2·a(n-1) - a(n-3) + a(floor(n/2)) + a(floor(n/3)) + ... + a(floor(n/n)), where a(0) = 1, a(1) = 2, a(2) = 3. A298407
Place a(n) red and b(n) blue balls in an urn; draw 6 balls without replacement; Probability(6 red balls)=Probability(4 red and 2 blue balls); binomial(a(n),6)=binomial(a(n),4)*binomial(b(n),2). A179123
The number of triangles in an equipotential triangle divided by medians into n rows of smaller triangles. A210687