Properties of the Number 21661

Twenty-One Thousand Six Hundred Sixty-One

Basics

Value: 21660 → 21661 → 21662

Parity: odd

Prime: Yes

Previous Prime: 21649

Next Prime: 21673

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 21661

Divisors: 1, 21661

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010010011101

Octal: 52235

Duodecimal: 10651

Hexadecimal: 549d

Square: 469198921

Square Root: 147.1767644704829

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 that divide at least one term of Sylvester's sequence s = A000058: s(n+1) = s(n)² - s(n) + 1, s(0) = 2. A7996

Class 6+ primes. A81634

T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock commuting with each horizontal and vertical neighbor 3X3 subblock. A186881

Primes having only {1, 2, 6} as digits. A385774

Primes p such that p-12, p and p+12 are consecutive primes. A53072

Primes of the form T(k) + S(k) + 1 where T(k) is the k-th triangular number and S(k) is the k-th square number. A229080

Primes such that the sum of the factorials of the digits is a perfect square. A52279

a(n) = 60·n² + 1. A158673

Balanced primes of order one ending in 1. A303092

Lesser of consecutive primes whose sum is a palindromic number. A242386