Properties of the Number 21055

Twenty-One Thousand Fifty-Five

Basics

Value: 21054 → 21055 → 21056

Parity: odd

Prime: No

Previous Prime: 21031

Next Prime: 21059

Digit Sum: 13

Digital Root: 4

Palindrome: No

Factorization: 5 × 4211

Divisors: 1, 5, 4211, 21055

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

8509 Try Today's Challenge

Representations

Binary: 101001000111111

Octal: 51077

Duodecimal: 10227

Hexadecimal: 523f

Square: 443313025

Square Root: 145.10341140028376

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

T(n,k)=Number of nXk 0..1 arrays with no 1 equal to more than four of its king-move neighbors. A282316

Times in hours,minutes and seconds (to the nearest second) at which the smoothly crossing minute and hour hands of an analog clock coincide, over a period of one complete 12-hour sweep of the hour hand. A120500

a(1) = 1; thereafter a(n) is always the smallest integer > a(n-1) not leading to a contradiction, such that any five consecutive digits in the sequence sum up to a prime. A152605

Times in hours, minutes and seconds (to the nearest second) at which the hour and minute hands of an analog clock, if interchanged, continue to indicate some other albeit accurate times, over a complete 12-hour sweep for the slower hand. Leading zeros omitted. A121577

Number of nX2 0..2 arrays with rows and columns lexicographically nondecreasing and the instance counts of every value within one of each other. A201426

Number of n X 3 0..1 arrays with no 1 equal to more than four of its king-move neighbors. A282311

Number of nX5 0..1 arrays with no 1 equal to more than four of its king-move neighbors. A282313

Squares with property that all even digits occur together and all odd digits occur together. A30476

Decimal expansion of 1/51. A21055