Properties of the Number 21751

Twenty-One Thousand Seven Hundred Fifty-One

Basics

Value: 21750 → 21751 → 21752

Parity: odd

Prime: Yes

Previous Prime: 21739

Next Prime: 21757

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 21751

Divisors: 1, 21751

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 101010011110111

Octal: 52367

Duodecimal: 10707

Hexadecimal: 54f7

Square: 473106001

Square Root: 147.4822023160761

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

Partial sums of A000009 (partitions into distinct parts). A36469

Primes p such that p-1 and p+1 each contain at least one cubed prime in their prime factorization. A162870

Expansion of g.f. (1-2·x+51·x²)/(1-x)³. A257352

The Gi1 and Gi2 sums of Losanitsch's triangle A034851. A192928

The·member of the positive proper fundamental solution (x = x1(n), y = y1(n)) of the first class for the Pell equation x² - D(n)*y² = +8 for odd D(n) = A263012(n). A264349

G.f. A(x) satisfies A(x) = 1 / ((1 - x) * (1 - x·A(x³))). A367691

a(n) = ∑_{i=1..A328404(n)} (A276086(n) mod prime(i))*A002110(i-1), where A276086 is the primorial base exp-function, and A328404(n) gives the length of A276086(n) in primorial base representation. A391936

Prime lucky numbers k (from A031157) such that nextprime(k)=nextlucky(k). A57698

Primes of the form k² - 7·k + 7. A89376

a(1) = 2; a(n + 1) = smallest prime > a(n) such that a(n + 1) - a(n) is the product of 7 primes. A285692