5645
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 6780
- Proper Divisor Sum (Aliquot Sum)
- 1135
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4512
- Möbius Function
- 1
- Radical
- 5645
- 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
- 36
- 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
- Simple triangulations of a disk: column 4 of square array in A210664.at n=7A004305
- Numbers k such that 7!*(2k-8)!/(k!*(k-1)!) is an integer.at n=6A004787
- Convolution of Fibonacci numbers 1,2,3,5,... with themselves.at n=12A004798
- a(n) = (n+1)*(14*n^3+13*n^2+6*n+1).at n=4A027850
- Numerators of continued fraction convergents to sqrt(683).at n=4A042312
- Numbers whose base-5 representation contains exactly three 0's and two 4's.at n=11A045216
- a(n) = Sum_{i=0..floor(n/2)} T(2i,n-2i), array T as in A049735.at n=17A049738
- Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 2.at n=44A051967
- a(n) = 5*(n^2 - n + 2)/2.at n=48A082450
- A014486-indices of symmetric binary trees.at n=19A083940
- Indices of primes in sequence defined by A(0) = 81, A(n) = 10*A(n-1) + 61 for n > 0.at n=6A101076
- Indices of primes in sequence defined by A(0) = 37, A(n) = 10*A(n-1) - 13 for n > 0.at n=8A101837
- Sieve performed by successive iterations of steps where step m is: keep m terms, remove the next 3 and repeat; as m = 1,2,3,.. the remaining terms form this sequence.at n=13A112561
- Smaller of two consecutive semiprimes with the same digital root.at n=36A118699
- a(n) = 7 + floor((1 + Sum_{j=1..n-1} a(j))/4).at n=30A120165
- Erroneous duplicate version of A181496.at n=9A165146
- Number of (n+1) X 2 0..2 arrays with rows and columns in nondecreasing order and with no 2 X 2 subblock sum differing from a horizontal or vertical neighbor subblock sum by more than one.at n=7A184073
- Number of (n+1)X9 0..2 arrays with rows and columns in nondecreasing order and with no 2X2 subblock sum differing from a horizontal or vertical neighbor subblock sum by more than one.at n=0A184080
- T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with rows and columns in nondecreasing order and with no 2X2 subblock sum differing from a horizontal or vertical neighbor subblock sum by more than one.at n=28A184081
- T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with rows and columns in nondecreasing order and with no 2X2 subblock sum differing from a horizontal or vertical neighbor subblock sum by more than one.at n=35A184081