13217
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 13218
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 13216
- Möbius Function
- -1
- Radical
- 13217
- 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
- 50
- 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
- yes
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1571
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Numbers k such that the continued fraction for sqrt(k) has period 77.at n=17A020416
- a(n) = s(1)*t(n) + s(2)*t(n-1) + ... + s(k)*t(n+1-k), where k = [ (n+1)/2 ], s = (Fibonacci numbers), t = (Lucas numbers).at n=15A024459
- s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (Fibonacci numbers), t = (Lucas numbers).at n=14A025079
- Primes of the form k^2 - 8.at n=24A028886
- Numbers n such that 241*2^n-1 is prime.at n=12A050879
- Primes p such that x^59 = 2 has no solution mod p.at n=30A059312
- Lesser of irregular twin primes.at n=38A060012
- Lesser of twin primes whose average is 6 times a prime.at n=33A060213
- Irregular primes with irregularity index three.at n=19A060975
- n*10^3-1, n*10^3-3, n*10^3-7 and n*10^3-9 are all prime.at n=9A064977
- a(n) is smallest prime > 10*a(n-1), a(1) = 13.at n=3A065539
- Lesser prime factor of semiprimes in A089542.at n=29A089543
- "Secondary twin primes": a(n) = A006450(A096477(n)).at n=31A096479
- Primes p such that p^2 is an interprime = average of two successive primes.at n=41A123993
- Primes congruent to 8 mod 37.at n=38A142117
- Primes congruent to 15 mod 41.at n=31A142212
- Primes congruent to 16 mod 43.at n=36A142265
- Primes congruent to 10 mod 47.at n=36A142361
- Primes congruent to 36 mod 49.at n=37A142444
- Primes congruent to 20 mod 53.at n=28A142550