Properties of the Number 20858

Twenty Thousand Eight Hundred Fifty-Eight

Basics

Value: 20857 → 20858 → 20859

Parity: even

Prime: No

Previous Prime: 20857

Next Prime: 20873

Digit Sum: 23

Digital Root: 5

Palindrome: No

Factorization: 2 × 10429

Divisors: 1, 2, 10429, 20858

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 101000101111010

Octal: 50572

Duodecimal: 100A2

Hexadecimal: 517a

Square: 435056164

Square Root: 144.42298985964803

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

Dirichlet inverse of A124859. A354359

a(n) = ∑_i=1..n (i-1)*T(i)², where T(i) = A000073(i) is the i-th tribonacci number. A337284

Convolution of Fibonacci and Jacobsthal numbers. A94687

Numbers k such that the continued fraction for sqrt(k) has period 35. A20374

Triangle of numbers {a(n,k), n >= 0, 0<=k<=n} defined by a(0,0)=1, a(1,0)=2, a(n,0)=A006318(n), a(n,n)=A006319(n), a(n+1,0)=a(n,0)+a(n,n), a(n,m+1)= Sum A006318(k)*a(n-k,0), k=0..m. A73150

Number of partitions of n not containing 2*(number of parts) as a part. A238488

Triangle read by rows given by [1,1,1,1,1,1,1,1,1,1,...] δ [1,1,0,0,0,0,0,0,0,0,0,...] where δ is the operator defined in A084938. A167685

a(n) = prime(n)# - ∑_k=1..n-1 prime(k)# * a(n-k), where prime()# = A002110. A333372

Decimal expansion of log₂(5). A20858

a(1) = 1; for n > 1, a(n) is the smallest positive integer that has not yet appeared which shares no digit with the sum of all previous terms a(1)..a(n-1). A368181