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Properties of the Number 31780

Thirty-One Thousand Seven Hundred Eighty

Basics

Value: 31779 → 31780 → 31781

Parity: even

Prime: No

Previous Prime: 31771

Next Prime: 31793

Digit Sum: 19

Digital Root: 1

Palindrome: No

Factorization: 2 2 × 5 × 7 × 227

Divisors: 1, 2, 4, 5, 7, 10, 14, 20, 28, 35

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 111110000100100

Octal: 76044

Duodecimal: 16484

Hexadecimal: 7c24

Square: 1009968400

Square Root: 178.26945896591485

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

Dimension of space of invariants of n-th tensor power of 7-dimensional irreducible representation of G2. Also the number of n-leaf, otherwise trivalent graphs in a disk such that all faces have at least 6 sides. A59710
Structured triakis tetrahedral numbers (vertex structure 4). A100175
Number of ternary rooted identity (distinct subtrees) trees with n nodes. A116379
Triangle read by rows giving the coefficients of general sum formulas of n-th Subfactorial numbers (A000166). The k-th row (k>=1) contains T(i,k) for i=1 to 2·k-1, where T(i,k) satisfies Subf(n) = ∑k=1..n ∑i=1..2·k-1 T(i,k) * C(n-k,i-1) * nn-k. A101560
Numbers k such that the k-th triangular number contains only digits {0,5,9}. A119086
a(n) is the sum of the non-Fibonacci numbers in row n of array T given by A027935, computed as T(n,m) + T(n,m+1) + ... + T(n,n-1), where m = floor((n+2)/2). A27946
Numbers which when multiplied by any repunit prime Rp give a Smith number. A104167
a(n) = (2·n-3-(-1)n)*(22·n2-21·n+5·n*(-1)n)/96. A298992
a(n) = floor(10000·log(n)). A4243
Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 12 ones. A31780