16109
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 16380
- Proper Divisor Sum (Aliquot Sum)
- 271
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 15840
- Möbius Function
- 1
- Radical
- 16109
- 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
- 71
- 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) = prime(n)*(prime(n-1)-1)/2.at n=39A014302
- a(n) = 11 a(n-1) + 4 a(n-2).at n=5A015596
- a(n) = a(1) + a(2) + ... + a(n-1) + a(m), where m = 2^(p+1) + 2 - n and p is the unique integer such that 2^p < n-1 <= 2^(p+1), starting with a(1) = a(2) = 1.at n=14A049941
- Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 17.at n=17A051982
- Starting positions of strings of three 6's in the decimal expansion of Pi.at n=11A083625
- Semiprimes that are the sum of the first n semiprimes for some n.at n=25A092190
- The difference between the largest part and the smallest part summed over all those partitions of n in which every integer from the smallest part to the largest part occurs.at n=48A117471
- Expansion of x^2/(1 -2*x -121*x^2).at n=5A123006
- a(n) = 8*n^2 + 14*n + 5.at n=44A181890
- a(n) is the smallest prefix such that the numbers with k digits "3" appended are primes for k = 1..n.at n=5A186069
- Number of nX3 0..1 arrays avoiding 0 0 1 horizontally and 0 1 1 vertically.at n=5A206780
- Number of nX6 0..1 arrays avoiding 0 0 1 horizontally and 0 1 1 vertically.at n=2A206783
- T(n,k) = Number of n X k 0..1 arrays avoiding 0 0 1 horizontally and 0 1 1 vertically.at n=30A206785
- T(n,k) = Number of n X k 0..1 arrays avoiding 0 0 1 horizontally and 0 1 1 vertically.at n=33A206785
- T(n,k)=Number of nXk 0..1 arrays avoiding 0 1 0 horizontally and 0 1 1 vertically.at n=33A207000
- Number of 6Xn 0..1 arrays avoiding 0 1 0 horizontally and 0 1 1 vertically.at n=2A207003
- Lucas pseudoprimes.at n=14A217120
- Strong Lucas pseudoprimes.at n=3A217255
- Number of cyclotomic cosets of 11 mod 10^n.at n=44A220021
- Numbers of the form p*q, p and q prime with q=2*p+3.at n=12A226754