Properties of the Number 20825

Twenty Thousand Eight Hundred Twenty-Five

Basics

Value: 20824 → 20825 → 20826

Parity: odd

Prime: No

Previous Prime: 20809

Next Prime: 20849

Digit Sum: 17

Digital Root: 8

Palindrome: No

Factorization: 5 ² × 7 ² × 17

Divisors: 1, 5, 7, 17, 25, 35, 49, 85, 119, 175

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: Yes

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Representations

Binary: 101000101011001

Octal: 50531

Duodecimal: 10075

Hexadecimal: 5159

Square: 433680625

Square Root: 144.30869689661813

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

Binomial coefficient C(n,48). A11001

a(n) = 1² + 3² + 5² + 7² + ... + (2·n-1)² = n*(4·n² - 1)/3. A447

a(n) = n*(n+1)²/2. A6002

Dodecahedral numbers: a(n) = n*(3·n - 1)*(3·n - 2)/2. A6566

a(n) = 17·n². A244630

Odd tetrahedral numbers: a(n) = (4·n+1)*(4·n+2)*(4·n+3)/6. A15219

Numerators in the fractional coefficients that form the partial quotients of the continued fraction representation of the inverse tangent of 1/x. A110255

Numerators in the coefficients that form the odd-indexed partial quotients of the continued fraction representation of the inverse tangent of 1/x. A110257

Sum of the fourth largest parts in the partitions of n into 7 parts. A308930

Triangle where the g.f. of column k is 1/(1-x)^k² for k>=1, as read by rows n>=1. A214398