3181
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 3182
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 3180
- Möbius Function
- -1
- Radical
- 3181
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- no
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- no
- Lucas Number
- no
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 105
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 450
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes with 7 as smallest primitive root.at n=31A001126
- Primes p such that the multiplicative order of 2 modulo p is (p-1)/3.at n=34A001133
- a(n) = (5*n + 1)^2 + 4*n + 1.at n=11A007533
- Coordination sequence T3 for Zeolite Code EUO.at n=35A008098
- a(0) = 1, a(n) = 11*n^2 + 2 for n>0.at n=17A010003
- Numbers k such that the continued fraction for sqrt(k) has period 3.at n=14A013643
- Super-3 Numbers (3n^3 contains substring '333' in its decimal expansion).at n=28A014569
- Fibonacci sequence beginning 5, 19.at n=12A022143
- Primes that remain prime through 2 iterations of the function f(x) = 2x + 5.at n=41A023243
- Primes that remain prime through 2 iterations of function f(x) = 3x + 8.at n=35A023248
- Primes that remain prime through 2 iterations of function f(x) = 5x + 2.at n=36A023252
- Primes that remain prime through 3 iterations of function f(x) = 3x + 8.at n=4A023279
- Primes that remain prime through 3 iterations of function f(x) = 5x + 2.at n=8A023283
- Primes that remain prime through 4 iterations of function f(x) = 3x + 8.at n=0A023309
- Primes that remain prime through 5 iterations of function f(x) = 3x + 8.at n=0A023337
- a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-1)*a(1) for n >= 5, starting 1,1,1,0.at n=11A025274
- T(2n,n-1), T given by A026681.at n=5A026683
- Number of partitions of n into an even number of parts, the least being 6; also, a(n+6) = number of partitions of n into an odd number of parts, each >=6.at n=74A027198
- Squarefree n such that Q(sqrt(n)) has class number 5.at n=22A029705
- Values of Newton-Gregory forward interpolating polynomial (1/6)*(4*n^4 - 60*n^3 + 347*n^2 - 927*n + 978).at n=12A030442