6217
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 6218
- 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
- 6216
- Möbius Function
- -1
- Radical
- 6217
- 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
- 111
- 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
- 809
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- One-half the number of permutations of length n with exactly 1 rising or falling successions.at n=8A000130
- Primes p such that the multiplicative order of 2 modulo p is (p-1)/6.at n=42A001136
- Number of connected functions (or mapping patterns) on n unlabeled points, or number of rings and branches with n edges.at n=10A002861
- Coordination sequence for sigma-CrFe, Position Xb.at n=20A009960
- Triangle read by rows: T(n,k) is one-half the number of permutations of length n with exactly n-k rising or falling successions, for n >= 1, 1 <= k <= n. T(1,1) = 1 by convention.at n=34A010028
- Numbers k such that the continued fraction for sqrt(k) has period 93.at n=2A020432
- Primes that remain prime through 3 iterations of function f(x) = 2x + 3.at n=16A023273
- a(n) = floor(Sum_{1<=i<j<=n} (sqrt(j)-sqrt(i))^2).at n=47A025196
- Palindromic primes in base 4.at n=22A029972
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted then there are a pair of central terms both equal to 7.at n=15A031420
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 36 ones.at n=23A031804
- Numbers whose set of base-8 digits is {1,4}.at n=38A032820
- Positive numbers having the same set of digits in base 6 and base 8.at n=38A037435
- a(n) = (9*n^2 + 3*n + 2)/2.at n=37A038764
- Numbers having four 4's in base 6.at n=17A043388
- Numbers having four 1's in base 8.at n=25A043428
- Primes with first digit 6.at n=43A045712
- Least prime in A023200 (lesser of 4-twins) such that the distance to the next 4-twin is 6*n.at n=41A052351
- Primes of the form k(k+1)/2+1 (i.e., central polygonal numbers, or one more than triangular numbers).at n=33A055469
- Let prime(i) = i-th prime, let twin(n) = (P,Q) be n-th pair of twin primes; sequence gives prime(P).at n=30A057470