Properties of the Number 19981

Nineteen Thousand Nine Hundred Eighty-One

Basics

Value: 19980 → 19981 → 19982

Parity: odd

Prime: No

Previous Prime: 19979

Next Prime: 19991

Digit Sum: 28

Digital Root: 1

Palindrome: No

Factorization: 13 × 29 × 53

Divisors: 1, 13, 29, 53, 377, 689, 1537, 19981

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100111000001101

Octal: 47015

Duodecimal: B691

Hexadecimal: 4e0d

Square: 399240361

Square Root: 141.35416513141735

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

T(n,k)=Number of length n+2 0..k arrays with the sum of second differences squared multiplied by some arrangement of +-1 equal to zero. A250320

5-Stirling numbers of the second kind. A193685

a(n) is the number of integer partitions of n for which the largest part is equal to the index of the seaweed algebra formed by the integer partition paired with its weight. A318203

Expansion of 1/((1-5·x)(1-6·x)(1-7·x)). A19757

a(n) is the number of vertices formed by n-secting the angles of a nonagon (enneagon). A335782

Number of unlabeled rooted trees with n nodes such that the minimal outdegree of inner nodes equals 4. A244458

a(n) is the smallest k such that number of non-unitary prime divisors of central binomial coefficient, A001405(k) = C(k, floor(k/2)) equals n. A81394

Structured pentagonal icositetrahedral numbers (vertex structure 13). A100167

Number of sets of exactly n positive integers <= n+5 having a square element sum. A281968

Centered 30-gonal numbers. A389799