Properties of the Number 21247

Twenty-One Thousand Two Hundred Forty-Seven

Basics

Value: 21246 → 21247 → 21248

Parity: odd

Prime: Yes

Previous Prime: 21227

Next Prime: 21269

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 21247

Divisors: 1, 21247

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001011111111

Octal: 51377

Duodecimal: 10367

Hexadecimal: 52ff

Square: 451435009

Square Root: 145.76350709282485

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

Number of integer compositions of n that are the first sums of some composition. A391683

Start with a single hexagon; at n-th generation add a hexagon at each expandable vertex (this is the "vertex to side" version); a(n) is the sum of all label values at n-th generation. (See comment for construction rules.) A247905

Positions of records in A166133. A256404

Primes congruent to 7 mod 59. A142734

Lexicographically largest strictly increasing sequence of primes for which the continued square root map produces Feigenbaum's constant δ = 4.6692016... (A006890). A257809

Primes P where the distance to the nearest prime is greater than 2·log(P). A330426

Prime numbers, isolated from neighboring primes by >16. A137875

Numbers n such that A166133(n) sets a new record and also satisfies A166133(n)=A166133(n-1)²-1. A256422

Numbers k such that k and k+4 are consecutive cubefree numbers. A349235

Index in A353715 of the first term divisible by 2ⁿ and no higher power of 2, or -1 if no such term exists. A353727