Properties of the Number 21528

Twenty-One Thousand Five Hundred Twenty-Eight

Basics

Value: 21527 → 21528 → 21529

Parity: even

Prime: No

Previous Prime: 21523

Next Prime: 21529

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 2 ³ × 3 ² × 13 × 23

Divisors: 1, 2, 3, 4, 6, 8, 9, 12, 13, 18

Polygonal

Triangular: Yes

Square: No

Pentagonal: No

Hexagonal: Yes

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010000011000

Octal: 52030

Duodecimal: 10560

Hexadecimal: 5418

Square: 463454784

Square Root: 146.7242311276498

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

Triangular numbers that are the product of two triangular numbers greater than 1. A188630

Triangular numbers which are products of triangular numbers larger than 1. A68143

Product of the nonzero exponents in the prime factorization of n!. A135291

a(n) = n*(n+1)*(7·n+2)/6. A255211

Numbers k such that 2k-1 divides 2^k-1. A81856

Numbers k such that sopfr(k)=τ(k). A78511

Numbers with a minimum of 6 polygonal roots, excluding itself. A275256

a(n) = ∑_i=0..n digsum(i)³, where digsum(i) = A007953(i). A231688

Triangle read by rows. A generalization of unsigned Lah numbers, called L[3,1]. A290596

The first of two consecutive triangular numbers the sum of which is equal to the sum of two consecutive prime numbers. A298462