Properties of the Number 21057

Twenty-One Thousand Fifty-Seven

Basics

Value: 21056 → 21057 → 21058

Parity: odd

Prime: No

Previous Prime: 21031

Next Prime: 21059

Digit Sum: 15

Digital Root: 6

Palindrome: No

Factorization: 3 × 7019

Divisors: 1, 3, 7019, 21057

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001001000001

Octal: 51101

Duodecimal: 10229

Hexadecimal: 5241

Square: 443397249

Square Root: 145.11030287336595

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

Expansion of ∏_k>=1 1/(1-x^3·k-1)^k. A262876

Number of nonisomorphic ways a loop can cross three roads meeting in a Y n times (orbits under symmetry group of order 6). A78105

a(n) = A273059(4n+1). A275917

Numbers k such that 6·R_k - 5 is prime, where R_k = 11...1 is the repunit (A002275) of length k. A98088

Number of nX4 0..1 arrays with each 1 horizontally, vertically or antidiagonally adjacent to 2 or 3 neighboring 1s. A296401

Decimal expansion of 1/53. A21057