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Properties of the Number 20820

Twenty Thousand Eight Hundred Twenty

Basics

Value: 20819 → 20820 → 20821

Parity: even

Prime: No

Previous Prime: 20809

Next Prime: 20849

Digit Sum: 12

Digital Root: 3

Palindrome: No

Factorization: 2 2 × 3 × 5 × 347

Divisors: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101000101010100

Octal: 50524

Duodecimal: 10070

Hexadecimal: 5154

Square: 433472400

Square Root: 144.29137188342204

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 (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row, column, diagonal and antidiagonal sum not equal to 0 2 4 6 or 7. A252457
Expansion of ∏k>=1 1/(1-xk+8)k. A263364
Number of isomorphism classes of nanocones with 3 pentagons and a nearsymmetric boundary of length n. A198014
Integer part of square root of n-th Fibonacci number. A61287
Numbers such that the digital sum base 2 and the digital sum base 3 and the digital sum base 4 all are equal. A135122
Sum of all prime encoded perfect partitions of n. A360713
Number of mobiles (circular rooted trees) with n nodes and 3 leaves. A55341
a(n) = 10prime(n-1) mod prime(n)2. A265012
Numbers k such that φ(k)+σ(k) is a perfect cube. A61366
a(n) = floor(11n/7n). A94993