Properties of the Number 21489

Twenty-One Thousand Four Hundred Eighty-Nine

Basics

Value: 21488 → 21489 → 21490

Parity: odd

Prime: No

Previous Prime: 21487

Next Prime: 21491

Digit Sum: 24

Digital Root: 6

Palindrome: No

Factorization: 3 × 13 × 19 × 29

Divisors: 1, 3, 13, 19, 29, 39, 57, 87, 247, 377

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101001111110001

Octal: 51761

Duodecimal: 10529

Hexadecimal: 53f1

Square: 461777121

Square Root: 146.59126849850233

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

Numbers k such that k and k+1 have 4 distinct prime factors. A140078

One ninth of deca-factorial numbers. A35278

a(0) = 0; a(1)=1; for n>1, a(n) = least positive integer m not among a(1),...,a(n-1) such that |m-a(n-1)| > |a(n-1)-a(n-2)|. A78783

T(n,k)=Number of nXk 0..1 arrays with each 1 horizontally or vertically adjacent to 1, 2 or 4 1s. A295531

Numbers k such that k and k+1 each have at least 4 distinct prime factors. A321504

a(1)=1, a(2)=2, a(3)=3; for n >= 3, a(n) is smallest number such that all a(i) for 1 <= i <= n are distinct, all a(i)+a(j) for 1 <= i < j <= n are distinct and all a(i)+a(j)+a(k) for 1 <= i < j < k <= n are distinct. A36241

Product of all primes p such that 2n - p is also prime. A238711

Numbers k such that k and k+1 are the product of exactly four distinct primes. A318896

Number at end of segment n of A078783. A117072

Triangle read by rows: T(n,k) is the number of partitions of the set {1,2,...,n} having exactly k blocks that do not consist of consecutive integers (0<=k<=floor(n/2); a singleton is considered a block of consecutive integers). A177256