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Properties of the Number 21125

Twenty-One Thousand One Hundred Twenty-Five

Basics

Value: 21124 → 21125 → 21126

Parity: odd

Prime: No

Previous Prime: 21121

Next Prime: 21139

Digit Sum: 11

Digital Root: 2

Palindrome: No

Factorization: 5 3 × 13 2

Divisors: 1, 5, 13, 25, 65, 125, 169, 325, 845, 1625

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101001010000101

Octal: 51205

Duodecimal: 10285

Hexadecimal: 5285

Square: 446265625

Square Root: 145.34441853748632

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

Least hypotenuse of n distinct Pythagorean triangles. A6339
Numbers of the form p2 * q3, where p,q are distinct primes. A143610
Numbers n that are the hypotenuse of exactly 17 distinct integer-sided right triangles, i.e., n2 can be written as a sum of two squares in 17 ways. A97239
10-gonal (or decagonal) pyramidal numbers: a(n) = n*(n + 1)*(8·n - 5)/6. A7585
Numbers of the form q1b1 * q2b2 * q3b3 * q4b4 * q5b5 * ... where q1=5, q2=13, q3=17, q4=29, q5=37, ... (A002144) and b1 >= b2 >= b3 >= b4 >= b5 >= .... A54994
Column 4 of an array closely related to A083480. (Both arrays have shape sequence A083479). A89574
Determinant of the n X n matrix with (i,j)-entry equal to 1 or 0 according as 2*(i + j) - 1 and 2*(i + j) + 1 are twin primes or not. A228615
Numbers of the form (5i)*(13j). A107466
T(n,k)=Rolling icosahedron footprints: number of nXk 0..11 arrays starting with 0 where 0..11 label vertices of an icosahedron and every array movement to a horizontal or antidiagonal neighbor moves along an icosahedral edge. A223321
Numbers n for which there are exactly six k such that n = k + (product of nonzero digits of k). A96927