Properties of the Number 21427

Twenty-One Thousand Four Hundred Twenty-Seven

Basics

Value: 21426 → 21427 → 21428

Parity: odd

Prime: No

Previous Prime: 21419

Next Prime: 21433

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 7 × 3061

Divisors: 1, 7, 3061, 21427

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101001110110011

Octal: 51663

Duodecimal: 10497

Hexadecimal: 53b3

Square: 459116329

Square Root: 146.3796433934719

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

Number of different forests of unrooted trees, without isolated vertices, on n labeled nodes. A105784

Numerators of partial sums of a series for the inverse of the arithmetic-geometric mean (agM) of 1/2 and 1. A130037

Total sum of parts of multiplicity 5 in all partitions of n. A222733

a(n) = ceiling(n*φ¹⁷), where φ is the golden ratio, A001622. A4972

Numbers n such that 8·10ⁿ + 2·R_n + 1 is prime, where R_n = 11...1 is the repunit (A002275) of length n. A103075

Numbers n such that n!3 + 3³ is prime. A247886

Number of (n+2) X (2+2) 0..3 arrays with every 3 X 3 subblock row and diagonal sum equal to 2 3 4 6 or 7 and every 3 X 3 column and antidiagonal sum not equal to 2 3 4 6 or 7. A252401

Result of inserting the integers n = 0, 1, 2, ... in this order into an initially empty list, where n is inserted between the pair of consecutive elements with sum equal to n and minimal absolute difference, or at the end of the list if no such pair exists. A360447

Repunits: (10ⁿ - 1)/9. Often denoted by R_n. A2275

Palindromic primes: prime numbers whose decimal expansion is a palindrome. A2385