16545
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 26496
- Proper Divisor Sum (Aliquot Sum)
- 9951
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8816
- Möbius Function
- -1
- Radical
- 16545
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 3
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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 97
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- Number of rooted projective plane trees with n nodes.at n=11A006080
- Expansion of 1/((1-x)(1-2x)(1-4x)(1-9x)).at n=4A021084
- The sum of the next n terms of A114103.at n=14A114105
- Ulam's spiral (SSW spoke).at n=32A143838
- Triangle T(n, k, j) = T(n-1, k, j) + T(n-1, k-1, j) + (2*j + 1)*prime(j)*T(n-2, k-1, j) with T(2, k, j) = prime(j) and j = 9, read by rows.at n=37A153654
- Triangle T(n, k, j) = T(n-1, k, j) + T(n-1, k-1, j) + (2*j + 1)*prime(j)*T(n-2, k-1, j) with T(2, k, j) = prime(j) and j = 9, read by rows.at n=43A153654
- Numbers k for which 5*k-4, 5*k-2, 5*k+2, and 5*k+4 are primes.at n=33A178082
- Number of length 5 1..(n+2) arrays with no leading or trailing partial sum equal to a prime and no consecutive values equal.at n=11A254222
- a(0)=0, a(1)=a(2)=a(3)=a(4)=1; thereafter, a(n) = Sum_{k=1..5} a(n-k-(a(n-k) mod 5)).at n=27A259615
- Number of integers in n-th generation of tree T(3/4) defined in Comments.at n=48A274146
- Values tilde(B_s(2)) of q-analogs of Fibonacci numbers.at n=12A279007
- Positions of pandigital 10-digit numbers after the decimal point in the decimal expansion of Pi.at n=7A280183
- Number of nX3 0..1 arrays with every element equal to 0, 3, 4, 5, 6, 7 or 8 king-move adjacent elements, with upper left element zero.at n=9A300133
- a(n) = 324*n^2 - 564*n + 321 (n>=1).at n=7A304617
- Number of n element multisets of the 10th roots of unity with zero sum.at n=38A321416
- Odd composite integers m such that A014448(m) == 4 (mod m).at n=32A335670
- Number of integer partitions of n without all different sums of two-element submultisets.at n=38A366753