2207
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 11
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 2208
- 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
- 2206
- Möbius Function
- -1
- Radical
- 2207
- 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
- yes
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 169
- 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
- yes
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 329
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Lucas numbers (beginning with 1): L(n) = L(n-1) + L(n-2) with L(1) = 1, L(2) = 3.at n=15A000204
- Primes p == 7, 19, 23 (mod 40) such that (p-1)/2 is also prime.at n=19A000353
- Primes with 5 as smallest primitive root.at n=48A001124
- a(0) = 3; thereafter, a(n) = a(n-1)^2 - 2.at n=3A001566
- Smallest primitive prime factor of Fibonacci number F(n), or 1 if F(n) has no primitive prime factor.at n=31A001578
- An infinite coprime sequence defined by recursion.at n=5A002715
- a(n) = round(n*phi^16), where phi is the golden ratio, A001622.at n=1A004951
- a(n) = ceiling(n*phi^16), where phi is the golden ratio, A001622.at n=1A004971
- a(n) = 3*a(n-2) - a(n-4), a(0)=2, a(1)=1, a(2)=3, a(3)=2. Alternates Lucas (A000032) and Fibonacci (A000045) sequences for even and odd n.at n=16A005247
- Bisection of Lucas numbers: a(n) = L(2*n) = A000032(2*n).at n=8A005248
- Safe primes p: (p-1)/2 is also prime.at n=41A005385
- Prime Lucas numbers (cf. A000032).at n=8A005479
- a(n) is the sum of products of terms in all partitions of n.at n=12A006906
- Primes of the form 2*k^2 + 29.at n=30A007641
- Coordination sequence T2 for Zeolite Code AFO.at n=31A008016
- Coordination sequence T1 for Zeolite Code STI.at n=32A008234
- a(n) = n^2 - 2.at n=46A008865
- a(0) = 1, a(n) = 5*n^2 + 2 for n>0.at n=21A010001
- Odd Lucas numbers.at n=10A014447
- Numbers n such that phi(n + 9) | sigma(n) for n not congruent to 0 (mod 3).at n=39A015849