Properties of the Number 20979

Twenty Thousand Nine Hundred Seventy-Nine

Basics

Value: 20978 → 20979 → 20980

Parity: odd

Prime: No

Previous Prime: 20963

Next Prime: 20981

Digit Sum: 27

Digital Root: 9

Palindrome: No

Factorization: 3 ⁴ × 7 × 37

Divisors: 1, 3, 7, 9, 21, 27, 37, 63, 81, 111

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101000111110011

Octal: 50763

Duodecimal: 10183

Hexadecimal: 51f3

Square: 440118441

Square Root: 144.84129245487972

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

T(n,k)=Number of nXk 0..1 arrays with no element equal to more than two of its horizontal, diagonal or antidiagonal neighbors, with the exception of exactly two elements, and with new values introduced in order 0 sequentially upwards. A281563

T(n,k)=Number of nXk 0..1 arrays with every element unequal to 1, 2, 3 or 5 king-move adjacent elements, with upper left element zero. A304019

Numbers that are the sum of four fourth powers in exactly two ways. A344193

Numbers that are the sum of four third powers in six or more ways. A345148

Sum of the two smallest parts from the partitions of 4n into 4 parts with smallest part = 1. A239059

Numbers that are the sum of four third powers in exactly six ways. A345149

G.f. satisfies A(x) = (1 + x) * (1 + x/A(x)³). A366327

Least number having n orderless representations as p² + q² + r², where p, q, and r are primes. A214512

Number of partitions of n such that m(1) = m(3), where m = multiplicity. A240058

Smallest number of triangulations of n points in the plane. A63544