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Properties of the Number 7819

Seven Thousand Eight Hundred Nineteen

Basics

Value: 7818 → 7819 → 7820

Parity: odd

Prime: No

Previous Prime: 7817

Next Prime: 7823

Digit Sum: 25

Digital Root: 7

Palindrome: No

Factorization: 7 × 1117

Divisors: 1, 7, 1117, 7819

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 1111010001011

Octal: 17213

Duodecimal: 4637

Hexadecimal: 1e8b

Square: 61136761

Square Root: 88.42510955605314

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

Triangle read by rows: T(n,k) is the number of even permutations of {1,2,...,n} having k descents (n >= 1, k >= 0). A145882
Square array A(n>=0,k>=1) (listed antidiagonally: A(0,1)=1, A(1,1)=1, A(0,2)=1, A(2,1)=2, A(1,2)=1, A(0,3)=1, A(3,1)=3, ...) giving the number of n-edge general plane trees fixed by k-fold application of Catalan Automorphisms A057511/A057512 (Deep rotation of general parenthesizations/plane trees). A79216
Sums of distinct powers of 6. A33043
Number of unlabeled balanced rooted semi-identity trees with n nodes. A306201
a(n) = ∑d∣n 6d-1. A339686
Number of Catalan objects fixed by two-fold application of the Catalan bijections A057511/A057512 (Deep rotation of general parenthesizations/plane trees). A79223
Positions in A218787 and A218788 of successive distinct values. A218611
a(n) = ∑d∣n nd-1. A308814
Triangle T(n,d) (listed row-wise: T(1,1)=1, T(2,1)=1, T(2,2)=1, T(3,1)=2, T(3,2)=2, T(3,3)=1, ...) giving the number of n-edge general plane trees with root degree d that are fixed by the two-fold application of Catalan Automorphisms A057511/A057512 (Deep rotation of general parenthesizations/plane trees). A79218
a(n+1) = 4·a(n) + 11·a(n-1) - 2·a(n-3). A122884