Properties of the Number 7991

Seven Thousand Nine Hundred Ninety-One

Basics

Value: 7990 → 7991 → 7992

Parity: odd

Prime: No

Previous Prime: 7963

Next Prime: 7993

Digit Sum: 26

Digital Root: 8

Palindrome: No

Factorization: 61 × 131

Divisors: 1, 61, 131, 7991

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 1111100110111

Octal: 17467

Duodecimal: 475B

Hexadecimal: 1f37

Square: 63856081

Square Root: 89.39239341241513

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

a(n) = n*(7·n + 11)/2 + 1. A198017

Convolution of partition numbers and Catalan numbers. A14329

Numbers n such that φ(n) = φ(n+12) and n is not divisible by 2. A217141

Number of partitions of n such that the number of parts having multiplicity >1 is not a part and the number of distinct parts is a part. A241410

Triangle read by rows: Take a pentagon with all diagonals drawn, as in A331929. Then T(n,k) = number of k-sided polygons in that figure for k = 3, 4, ..., n+5. A331939

Integer part of 5th root of product of first n primes. A127602

Least number m such that φ(m-6n) = φ(m) = φ(m+6n) and m is not divisible by n. A217068

Index of the first occurrence of prime(n) in A092938. A92939

a(n) = 6·n*(n-1) - 1. A103115

Numbers n such that 11ⁿ is the highest power of 11 dividing A240751(n). A286006