Properties of the Number 161

One Hundred Sixty-One

Basics

Value: 160 → 161 → 162

Parity: odd

Prime: No

Previous Prime: 157

Next Prime: 163

Digit Sum: 8

Digital Root: 8

Palindrome: Yes

Factorization: 7 × 23

Divisors: 1, 7, 23, 161

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 10100001

Octal: 241

Duodecimal: 115

Hexadecimal: a1

Square: 25921

Square Root: 12.68857754044952

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: Yes

OEIS Sequences

Semiprimes (or biprimes): products of two primes. A1358

Palindromes in base 10. A2113

Triangle read by rows: T(n,k) = ∑_j>=0 j!*T(n-j-1, k-1) for n >= 0, k >= 0. A84938

Squarefree semiprimes: Numbers that are the product of two distinct primes. A6881

a(n) = 4·n + 1. A16813

Numbers congruent to 1 or 5 mod 6. A7310

Fibbinary numbers: if n = F(i1) + F(i2) + ... + F(ik) is the Zeckendorf representation of n (i.e., write n in Fibonacci number system) then a(n) = 2^{i1 - 2} + 2^{i2 - 2} + ... + 2^{ik - 2}. Also numbers whose binary representation contains no two adjacent 1's. A3714

a(n) = 3·n + 2. A16789

a(n) is the number of partitions of n into at most 3 parts; also partitions of n+3 in which the greatest part is 3; also number of unlabeled multigraphs with 3 nodes and n edges. A1399

c-squarefree numbers: positive integers which in binary are concatenation of distinct parts of the form 10...0 with nonnegative number of zeros. A233564

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