Properties of the Number 21515

Twenty-One Thousand Five Hundred Fifteen

Basics

Value: 21514 → 21515 → 21516

Parity: odd

Prime: No

Previous Prime: 21503

Next Prime: 21517

Digit Sum: 14

Digital Root: 5

Palindrome: No

Factorization: 5 × 13 × 331

Divisors: 1, 5, 13, 65, 331, 1655, 4303, 21515

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010000001011

Octal: 52013

Duodecimal: 1054B

Hexadecimal: 540b

Square: 462895225

Square Root: 146.6799236432853

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 obtuse triangles, distinct up to congruence, on an n X n grid (or geoboard). A190022

Every prefix prime in base 6 (written in base 6). A24766

Number of ballot sequences of length n having 2 largest parts. A244099

G.f. satisfies A(x) = 1 + x·A(x)⁴ / (1 + x·A(x)⁵). A365224

Fibonacci sequence beginning 4, 11. A22131

Triangle read by rows: T(n,k) (k>=0) is the number of RNA secondary structures of size n (i.e., with n nodes) having k arcs that are covered by other arcs. A110317

Number of (n+2) X 9 0..1 matrices with each 3 X 3 subblock idempotent. A224558

Numbers k such that k!6 - 32 is prime, where k!6 is the sextuple factorial number (A085158). A289699

Intersection of A003052 and A283002. A283003

Triangle read by rows: T(n,k) gives the number of ballot sequences of length n having k largest parts, n >= k >= 0. A238123