Properties of the Number 21980

Twenty-One Thousand Nine Hundred Eighty

Basics

Value: 21979 → 21980 → 21981

Parity: even

Prime: No

Previous Prime: 21977

Next Prime: 21991

Digit Sum: 20

Digital Root: 2

Palindrome: No

Factorization: 2 ² × 5 × 7 × 157

Divisors: 1, 2, 4, 5, 7, 10, 14, 20, 28, 35

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010111011100

Octal: 52734

Duodecimal: 10878

Hexadecimal: 55dc

Square: 483120400

Square Root: 148.25653442597397

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) = n³ + n. A34262

a(n) = n OR n³ (applied to binary expansions). A8468

a(n) = 1000·n - 20. A157515

a(n) = 2·n*(9·n-1). A178574

2nd-order coefficients of the 1/N-expansion of traces of negative powers of complex Wishart matrices with parameter c=2. A277660

a(n) = ∑_k=1..n φ(gcd(k, n))³. A342535

a(n) = A078343(n) + (-1)ⁿ. A111955

a(n) = n XOR n³. A261807

p-INVERT of (0,1,0,1,0,1,...), where p(S) = (1 - S)⁵. A291225

a(n) = n*(n² + 1) if n is even, otherwise (n - 1/2)*(n² + 1). A71289