Properties of the Number 21940

Twenty-One Thousand Nine Hundred Forty

Basics

Value: 21939 → 21940 → 21941

Parity: even

Prime: No

Previous Prime: 21937

Next Prime: 21943

Digit Sum: 16

Digital Root: 7

Palindrome: No

Factorization: 2 ² × 5 × 1097

Divisors: 1, 2, 4, 5, 10, 20, 1097, 2194, 4388, 5485

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

2196 Try Today's Challenge

Representations

Binary: 101010110110100

Octal: 52664

Duodecimal: 10844

Hexadecimal: 55b4

Square: 481363600

Square Root: 148.12157169028418

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 (n+1)X(k+1) 0..2 arrays with every 2X2 subblock having nonzero determinant and having the same number of clockwise edge increases as its horizontal and vertical neighbors. A206128

Numbers that are the sum of ten fifth powers in three or more ways. A345635

Numbers that are the sum of ten fifth powers in exactly three ways. A346348

Triangle read by rows. Same rule as Aitken triangle (A011971) except T(0,0) = 1, T(1,0) = 2. A46937

Triangle, read by rows, where T(n,k) = T(n,k-1) + (k+1)*T(n-1,k) for n>k>0, T(n,0)=1 and T(n,n) = T(n,n-1) for n>=0. A102316

Interprimes which are of the form s·prime, s=20. A75295

Triangle read by rows: coefficients of chromatic polynomials for the poset of Dyck paths ordered by inclusion. A141622

Number of (n+1) X 2 0..2 arrays with every 2 X 2 subblock having nonzero determinant and having the same number of clockwise edge increases as its horizontal and vertical neighbors. A206121

Number of (n+1)X7 0..2 arrays with every 2X2 subblock having nonzero determinant and having the same number of clockwise edge increases as its horizontal and vertical neighbors. A206126

Numbers k that are a substring of xPy where k=concatenation(x,y) and xPy is the number of permutations A008279(x,y). A359012