Properties of the Number 61987

Sixty-One Thousand Nine Hundred Eighty-Seven

Basics

Value: 61986 → 61987 → 61988

Parity: odd

Prime: Yes

Previous Prime: 61981

Next Prime: 61991

Digit Sum: 31

Digital Root: 4

Palindrome: No

Factorization: 61987

Divisors: 1, 61987

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 1111001000100011

Octal: 171043

Duodecimal: 2BA57

Hexadecimal: f223

Square: 3842388169

Square Root: 248.97188596305406

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

Number of subsets of {1,...,n} containing two elements whose difference is 3. A209399

Number of times n-th distinct value is repeated in sequence b(k) = 1 + b(floor(k/2)) + b(floor(k/3)) with b(0) = 0, i.e., in A061984; also number of times n-th distinct row is repeated in square array T(n,k) = T(n-1,k) + T(n-1,floor(k/2)) + T(n-1,floor(k/3)) with T(0,0) = 1, i.e., in A061980. A61987

Equals two maps: number of nX4 binary arrays indicating the locations of corresponding elements equal to exactly two of their horizontal and antidiagonal neighbors in a random 0..2 nX4 array. A220933

Number of n X 4 0..1 arrays with every element equal to 0, 1, 2 or 4 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. A302318

G.f. satisfies: a(n) = [xⁿ] ( A(x)ⁿ⁺¹ + 1/A(x)ⁿ⁺¹ ) / (n+1) for n>1, with a(0)=a(1)=1. A243426