Properties of the Number 21490

Twenty-One Thousand Four Hundred Ninety

Basics

Value: 21489 → 21490 → 21491

Parity: even

Prime: No

Previous Prime: 21487

Next Prime: 21491

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 2 × 5 × 7 × 307

Divisors: 1, 2, 5, 7, 10, 14, 35, 70, 307, 614

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

8509 Try Today's Challenge

Representations

Binary: 101001111110010

Octal: 51762

Duodecimal: 1052A

Hexadecimal: 53f2

Square: 461820100

Square Root: 146.59467930317254

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

Weird numbers: abundant (A005101) but not pseudoperfect (A005835). A6037

Unitary weird numbers: unitary abundant (A034683) but not unitary pseudoperfect (A293188). A64114

Number T(n,k) of ordered set partitions of [n] where the maximal block size equals k; triangle T(n,k), n>=0, 0<=k<=n, read by rows. A276922

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

a(n) = n*(n² + 3)/2. A229183

a(n) = n*(16·n² + 3·n - 13)/6. A172078

a(n) = 3·a(n-1) - 2·a(n-2) with a(0)=28 and a(1)=70. A182465

Number at middle of segment n of A078783. A117071

Number of partitions of 2·n into distinct parts with exactly two odd parts. A96914

Number of ordered set partitions of [2n] where the maximal block size equals n. A276923