1965
domain: N
Properties
Digital Properties
- Digit Count
- 4
- 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
- 3168
- Proper Divisor Sum (Aliquot Sum)
- 1203
- 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
- 1040
- Möbius Function
- -1
- Radical
- 1965
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 143
- 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
- Total number of parts in all partitions of n. Also, sum of largest parts of all partitions of n.at n=17A006128
- Number of irreducible positions of size n in Montreal solitaire.at n=8A007075
- Coordination sequence T2 for Zeolite Code AFO.at n=29A008016
- Coordination sequence T1 for Zeolite Code BIK.at n=27A008047
- a(n) = floor( n*(n-1)*(n-2)/10 ).at n=28A011892
- Numbers k such that sigma(k) = sigma(k+13).at n=2A015883
- Sum of gcd(x, y) for 1 <= x, y <= n.at n=28A018806
- a(n) = Sum_{k >= 1} floor((1+sqrt(2))^(n-k)).at n=8A020962
- Numbers n such that n divides the (right) concatenation of all numbers <= n written in base 18 (most significant digit on right).at n=16A029511
- Lucky numbers with size of gaps equal to 12 (lower terms).at n=23A031894
- Denominators of continued fraction convergents to sqrt(919).at n=10A042777
- Base-4 palindromes that start with 1.at n=40A043003
- Numbers k such that 5 and 6 occur juxtaposed in the base-10 representation of k but not of k-1.at n=39A043251
- Numbers having three 3's in base 6.at n=23A043383
- Numbers whose base-7 representation contains exactly three 5's.at n=10A043415
- Numbers k such that 5 and 6 occur juxtaposed in the base-10 representation of k but not of k+1.at n=39A044031
- Numbers k such that string 0,5 occurs in the base 7 representation of k but not of k-1.at n=44A044143
- Numbers k such that string 5,5 occurs in the base 8 representation of k but not of k-1.at n=30A044232
- Numbers k such that string 2,3 occurs in the base 9 representation of k but not of k-1.at n=27A044272
- Numbers n such that string 6,5 occurs in the base 10 representation of n but not of n-1.at n=21A044397