Properties of the Number 21025

Twenty-One Thousand Twenty-Five

Basics

Value: 21024 → 21025 → 21026

Parity: odd

Prime: No

Previous Prime: 21023

Next Prime: 21031

Digit Sum: 10

Digital Root: 1

Palindrome: No

Factorization: 5 ² × 29 ²

Divisors: 1, 5, 25, 29, 145, 725, 841, 4205, 21025

Polygonal

Triangular: No

Square: Yes

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

4823 Try Today's Challenge

Representations

Binary: 101001000100001

Octal: 51041

Duodecimal: 10201

Hexadecimal: 5221

Square: 442050625

Square Root: 145

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

a(n) = (6·n + 1)². A16922

Numbers n that are the hypotenuse of exactly 12 distinct integer-sided right triangles, i.e., n² can be written as a sum of two squares in 12 ways. A97226

a(n) = (4·n + 1)². A16814

Number of n X 2 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 0 1 and 1 0 0 vertically. A207436

Main diagonal of A082043: a(n) = n⁴ + 2·n² + 1. A82044

Squares whose arithmetic mean of digits is an integer (i.e., the sum of digits is a multiple of the number of digits). A69711

a(n) = (5·n)². A16850

Cyclops squares: squares (A000290) that are also cyclops numbers (A134808). A160711

Crystal ball sequence for D₄ lattice. A7204

a(n) = (8·n + 1)². A17078