Properties of the Number 18940

Eighteen Thousand Nine Hundred Forty

Basics

Value: 18939 → 18940 → 18941

Parity: even

Prime: No

Previous Prime: 18919

Next Prime: 18947

Digit Sum: 22

Digital Root: 4

Palindrome: No

Factorization: 2 ² × 5 × 947

Divisors: 1, 2, 4, 5, 10, 20, 947, 1894, 3788, 4735

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 100100111111100

Octal: 44774

Duodecimal: AB64

Hexadecimal: 49fc

Square: 358723600

Square Root: 137.62267255071018

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 nXnXn triangular 0..k arrays with every horizontal row nondecreasing, first elements of rows nonincreasing, last elements of rows nondecreasing, and every row having the same average value. A215182

Numbers which are the sum of their proper divisors containing the digit 7. A59466

Expansion of (3 + x²) / (1 - x)⁴. A37237

Number of terms in the fully expanded n-th derivative of x^{x^x}. A281434

Values of·in solutions (x,y,z) to the Diophantine equation x³-x²+y³-y²=z³-z², with 1<x<y<z. A138667

Numbers m such that m²+1 is prime with (m-1)²+1 and (m+1)²+1 semiprimes. A321795

Expansion of c(x(1+2x)), c(x) the g.f. of A000108. A129147

Number of (n+1) X 4 binary arrays with rows and columns in nondecreasing order and with no 2 X 2 subblock sum differing from a horizontal or vertical neighbor subblock sum by more than one. A184065

Number of nX5 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 0 1 and 1 1 1 vertically. A207679

Number of nXnXn triangular 0..5 arrays with every horizontal row nondecreasing, first elements of rows nonincreasing, last elements of rows nondecreasing, and every row having the same average value. A215179