Properties of the Number 21870

Twenty-One Thousand Eight Hundred Seventy

Basics

Value: 21869 → 21870 → 21871

Parity: even

Prime: No

Previous Prime: 21863

Next Prime: 21871

Digit Sum: 18

Digital Root: 9

Palindrome: No

Factorization: 2 × 3 ⁷ × 5

Divisors: 1, 2, 3, 5, 6, 9, 10, 15, 18, 27

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010101101110

Octal: 52556

Duodecimal: 107A6

Hexadecimal: 556e

Square: 478296900

Square Root: 147.88509052639486

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: Yes

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

Numbers whose prime factors span an initial interval of prime numbers and whose sequence of prime multiplicities is a palindrome. A317087

Numbers of form 3ⁱ*10^j, with i, j >= 0. A25616

Sums of 2 distinct powers of 3. A38464

a(n) = (n³+n)*9ⁿ. A128074

Number of ternary trees (A001764) with n nodes and maximal diameter. A64017

Paradigm shift sequence for (0,2) production scheme with replacement. A246080

Numbers with prime signature {7,1,1}, i.e., of form p⁷*q·r with p, q and r distinct primes. A179696

Subset of A020342 (vampire numbers, definition 1) listing numbers which have more than one such representation of the desired form. A144563

a(n) = 30·n². A244636

McKay-Thompson series of class 3B for the Monster group with a(0) = -12. A30182