Properties of the Number 21001

Twenty-One Thousand One

Basics

Value: 21000 → 21001 → 21002

Parity: odd

Prime: Yes

Previous Prime: 20983

Next Prime: 21011

Digit Sum: 4

Digital Root: 4

Palindrome: No

Factorization: 21001

Divisors: 1, 21001

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101001000001001

Octal: 51011

Duodecimal: 101A1

Hexadecimal: 5209

Square: 441042001

Square Root: 144.91721774861674

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

Primes whose sum of digits is 4. A62339

Primes having only {0, 1, 2} as digits. A36953

Largest n-digit prime with minimum digit sum. A69664

a(1) = 1, a(2) = 2. For n >= 3, a(n) is found by concatenating the first n-1 terms of the sequence and then dividing the resulting number by a(n-1). A181754

"DHK[ 7 ]" (bracelet, identity, unlabeled, 7 parts) transform of 1,1,1,1,... A32248

Primes with maximal digit = 2. A106100

A239461(n) / n². A239464

a(1) = 2; a(n+1) is the smallest prime > a(n) which differs from it in every digit. A68853

Triangle T(n,k): number of ways of partitioning the n-element multiset {1,1,2,3,...,n-1} into exactly k nonempty parts, n>=1 and 1<=k<=n. A241500

Primes equal to an octagonal number plus 1. A285792