Properties of the Number 20018

Twenty Thousand Eighteen

Basics

Value: 20017 → 20018 → 20019

Parity: even

Prime: No

Previous Prime: 20011

Next Prime: 20021

Digit Sum: 11

Digital Root: 2

Palindrome: No

Factorization: 2 × 10009

Divisors: 1, 2, 10009, 20018

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 100111000110010

Octal: 47062

Duodecimal: B702

Hexadecimal: 4e32

Square: 400720324

Square Root: 141.48498153514387

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

Expansion of ∏_k>=1 (1 + x^k)^A000593(k). A301800

a(n) is the smallest k such that usigma(k) = A002110(n), or 0 if no such k exists. A291356

Expansion of 1/(1 - x*∑_k>=0 x^k³). A302019

Numbers k such that 8·10^k + 5·R_k + 2 is prime, where R_k = 11...1 is the repunit (A002275) of length k. A103085

Number of (n+3) X 7 0..2 matrices with each 4 X 4 subblock idempotent. A224724

Numbers n such that usigma(usigma(n))/usigma(n) > usigma(usigma(m))/usigma(m) for all m < n, where usigma(n) is the sum of unitary divisors of n (A034448). A289126

a(0) = a(1) = 1; a(n) = [xⁿ] ∏_k=1..n-1 (1 + x^a(k))/(1 - x^a(k)). A296387

Numbers with property that both the digit sum and the sum of the prime factors (counted with multiplicity) have only digits 0 and 1 in base 10. A297614

a(n) is the smallest number k such that ψ(k) = A001615(k) is the product of n distinct primes. A291144

T(n,k)=Number of (n+3)X(k+3) 0..2 matrices with each 4X4 subblock idempotent. A224728