Properties of the Number 21189

Twenty-One Thousand One Hundred Eighty-Nine

Basics

Value: 21188 → 21189 → 21190

Parity: odd

Prime: No

Previous Prime: 21187

Next Prime: 21191

Digit Sum: 21

Digital Root: 3

Palindrome: No

Factorization: 3 × 7 × 1009

Divisors: 1, 3, 7, 21, 1009, 3027, 7063, 21189

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001011000101

Octal: 51305

Duodecimal: 10319

Hexadecimal: 52c5

Square: 448973721

Square Root: 145.5644187293035

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

Interprimes (A024675) which are of the form s·prime, s=21. A75296

a(n) is the concatenation of n and 9n. A9474

Number of compositions (ordered partitions) of n into square pyramidal numbers (A000330). A322340

Smallest multiple of n beginning with n and having a digit sum n, or 0 if no such number exists. A77727

Lower Beatty array of sqrt(2). A182639

Let f(i) = prime( f(i - 1) (modulo 10ⁿ) ) with f(0) = 1; a(n) is the term where the period of the sequence f(i) begins to repeat. A130172

Indices of the triangular numbers in A189475. A358417

Riordan numbers: a(n) = (n-1)*(2·a(n-1) + 3·a(n-2))/(n+1). A5043

Number of n X n symmetric matrices with nonnegative entries and all row sums 2. A985

Number of n X n symmetric matrices with nonnegative integer entries, trace 0 and all row sums 2. A2137