Properties of the Number 20538

Twenty Thousand Five Hundred Thirty-Eight

Basics

Value: 20537 → 20538 → 20539

Parity: even

Prime: No

Previous Prime: 20533

Next Prime: 20543

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 2 × 3 ² × 7 × 163

Divisors: 1, 2, 3, 6, 7, 9, 14, 18, 21, 42

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101000000111010

Octal: 50072

Duodecimal: BA76

Hexadecimal: 503a

Square: 421809444

Square Root: 143.31085094995424

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

Twice-partitioned numbers where the first partition is strict and the latter partitions are constant. A279786

Numbers n that raised to the powers from 1 to k (with k>=1) are multiple of the sum of their digits (n raised to k+1 must not be a multiple). Case k=8. A135193

Larger of a non-unitary amicable pair. A259039

a(n) is the smallest k such that (k³ + 1)/(n³ + 1) is an integer > 1. A65964

Expansion of 1/(1 - x² - x⁷). A369813

a(n) = ∑_{k=0..floor(n/7)} C(n-5·k,2·k). A98574

Row sums of triangle A113993, where column k equals column 0 of A113983^k+1. A113997

Non-unitary amicable numbers. A259037

Numbers k such that k and k+1 are both terms in A377732. A377733

a(n) = ∑_{k=0..floor(2·n/7)} binomial(2·n-5·k,2·k). A392398