13687
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 25
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 13688
- 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
- 13686
- Möbius Function
- -1
- Radical
- 13687
- 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
- 138
- 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
- 1617
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Largest prime == 7 (mod 8) with class number 2n+1.at n=15A002147
- Primes that remain prime through 3 iterations of function f(x) = 5x + 2.at n=19A023283
- Primes that remain prime through 3 iterations of function f(x) = 6x + 7.at n=10A023289
- Primes that remain prime through 4 iterations of function f(x) = 5x + 2.at n=2A023313
- Primes of the form k^2 - 2.at n=28A028871
- Numbers whose base-4 representation contains exactly four 1's and three 3's.at n=21A045132
- Primes at which the difference pattern X424Y (X and Y >= 6) occurs in A001223.at n=18A052166
- Primes followed by a [4,2,4] prime difference pattern of A001223.at n=26A052378
- Sum_{k>=1} 1/(tanh(k*Pi) * k^(4n-1)) = Pi^(4n-1)*A057866(n)/A057867(n).at n=3A057866
- Primes of form p = 2 + Sum_{k = 1..m} k^2 for some m.at n=9A065244
- Lonely non-twin primes: non-twins sandwiched between two pairs of twins.at n=42A068016
- Primes that are 2 less than a perfect power m^k, k >= 2.at n=31A094786
- Solutions to A096509[x]=6; number of prime-powers [including primes] in the neighborhood of x with Ceiling[Log[x]] radius equals 6.at n=4A096517
- Primes of the form m^k-k, with m and k > 1.at n=38A099228
- Coefficients of Zeta(2*n+1) in a certain integer relation involving Ramanujan exponential-type sums.at n=6A119546
- Running prime totals of prime factors (without multiplicity) of consecutive composite N.at n=34A140610
- Primes of the form 210k + 37.at n=31A140847
- Primes congruent to 13 mod 43.at n=34A142262
- Primes congruent to 10 mod 47.at n=38A142361
- Primes congruent to 16 mod 49.at n=34A142427