Properties of the Number 21649

Twenty-One Thousand Six Hundred Forty-Nine

Basics

Value: 21648 → 21649 → 21650

Parity: odd

Prime: Yes

Previous Prime: 21647

Next Prime: 21661

Digit Sum: 22

Digital Root: 4

Palindrome: No

Factorization: 21649

Divisors: 1, 21649

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010010010001

Octal: 52221

Duodecimal: 10641

Hexadecimal: 5491

Square: 468679201

Square Root: 147.13599151805107

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

Smallest primitive factor of 10ⁿ - 1. Also smallest prime p such that 1/p has repeating decimal expansion of period n. A7138

Triangle of prime numbers in which n-th row lists all primes p such that 1/p has decimal period n, n >= 1. A46107

Irregular triangle read by rows in which row n lists prime factors (with multiplicity) of the repunit (10ⁿ - 1)/9 (A002275(n)). A102380

Primes p such that p, p+12, p+24 are consecutive primes. A52188

Smallest prime factor of repunit(n) = (10ⁿ-1)/9 (A002275). A67063

Smallest number with reciprocal of period length n in decimal (base 10). A3060

Table of prime factors of 10ⁿ - 1 (with multiplicity). A1270

Divisors of 10¹¹ - 1. A27896

Primes p such that A001175(p) = (p-1)/6. A308791

Primes p such that the decimal representation of 1/p does not contain every digit 0-9. A187614