13549
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 14364
- Proper Divisor Sum (Aliquot Sum)
- 815
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 12736
- Möbius Function
- 1
- Radical
- 13549
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 45
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- Squarefree Number
- yes
- Prime Power
- no
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- a(n) = (5*n + 1)^2 + 4*n + 1.at n=23A007533
- Numbers k such that the continued fraction for sqrt(k) has period 3.at n=33A013643
- Sum of digits in n-th term of A006711.at n=31A022480
- a(n) = (d(n)-r(n))/2, where d = A026057 and r is the periodic sequence with fundamental period (0,0,1,0).at n=47A026058
- Frobenius number of the numerical semigroup generated by three consecutive pentagonal numbers.at n=13A069757
- Number of pairs of consecutive prime (p,q) with q-p=6 and q < 10^n.at n=5A093738
- Positions of records in A034694.at n=42A120857
- A129957(n) - n*(n-1)/2.at n=24A129959
- Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 1000-1001-1111 pattern in any orientation.at n=11A147134
- a(n) = 25*n^2 - 36*n + 13.at n=24A154355
- a(n) = Sum_{k<=n} A000203(k)*(n-k+1), where A000203(m) is the sum of divisors of m.at n=35A175254
- Number of partitions p of n such that (number of even numbers in p) >= 2*(number of odd numbers in p).at n=46A241644
- Number of (n+2) X (2+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000001 or 00000011.at n=9A259717
- Sum of the third largest parts in the partitions of n into 6 parts.at n=41A308871
- Number of compositions (ordered partitions) of n into centered pentagonal numbers (A005891).at n=40A322801
- a(n) is the n-digit numerator of the fraction h/k with h and k coprime positive integers at which abs((h/k)^4-Pi) is minimal.at n=4A380099