Properties of the Number 21240

Twenty-One Thousand Two Hundred Forty

Basics

Value: 21239 → 21240 → 21241

Parity: even

Prime: No

Previous Prime: 21227

Next Prime: 21247

Digit Sum: 9

Digital Root: 9

Palindrome: No

Factorization: 2 ³ × 3 ² × 5 × 59

Divisors: 1, 2, 3, 4, 5, 6, 8, 9, 10, 12

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001011111000

Octal: 51370

Duodecimal: 10360

Hexadecimal: 52f8

Square: 451137600

Square Root: 145.73949361789343

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

Values of the difference d for 7 primes in arithmetic progression with the minimal start sequence {7 + j·d}, j = 0 to 6. A206041

Numbers that have exactly seven prime factors counted with multiplicity (A046308) whose digit reversal is different and also has 7 prime factors (with multiplicity). A109027

Irregular table read by rows: The number of k-faced polyhedra, where k>=4, created when an n-prism, formed from two n-sided regular polygons joined by n adjacent rectangles, is internally cut by all the planes defined by any three of its vertices. A338801

Values of the difference d for 6 primes in arithmetic progression with the minimal start sequence {7 + j·d}, j = 0 to 5. A206040

First differences of A069475, successive differences of (n+1)⁶-n⁶. A69476

12 times hexagonal numbers: 12·n*(2·n-1). A143698

a(n) = ∑_k=1..n φ(n·k). A372608

Sum of aliquot divisors of Ramanujan's highly composite numbers. A72824

Number of -3..3 arrays x(i) of n+1 elements i=1..n+1 with set{t,u,v in 0,1}((x[i+t]+x[j+u]+x[k+v])*(-1)^t+u+v) having four, six or eight distinct values for every i,j,k<=n. A211748

Least m>0 for which m + n² is a square and m + triangular(n) is a triangular number (A000217). A267140