4041
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 5850
- Proper Divisor Sum (Aliquot Sum)
- 1809
- 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
- 2688
- Möbius Function
- 0
- Radical
- 1347
- Omega Function (Ω)
- 3
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 144
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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) = n concatenated with n + 1.at n=39A001704
- Number of partitions of n into distinct parts, none being 5.at n=55A015750
- Numbers k such that the continued fraction for sqrt(k) has period 80.at n=11A020419
- a(n) = n*(25*n - 1)/2.at n=18A022282
- Numbers k such that Fibonacci(k) == 34 (mod k).at n=35A023180
- n written in fractional base 8/4.at n=41A024646
- Sequence satisfies T^2(a)=a, where T is defined below.at n=49A027591
- Pair up the numbers.at n=20A030656
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 44 ones.at n=4A031812
- Lucky numbers that are decimal concatenations of n with n + 1.at n=4A032651
- Number of different values of i^2 + j^2 + k^2 for i,j,k in [ 0,n ] (or [ -n,n ]).at n=46A034966
- Coordination sequence T3 for Zeolite Code STT.at n=42A038426
- Coordination sequence T15 for Zeolite Code STT.at n=42A038427
- a(n)=(s(n)+6)/10, where s(n)=n-th base 10 palindrome that starts with 4.at n=26A043083
- Concatenate "n" and "nextprime(n)".at n=39A049852
- Numbers n such that phi(n)^2 + sigma(n)^2 is an integer square.at n=44A067811
- Intersection of A068017 and A068019: numbers n such that both sigma(n) and phi(n) are middle terms between (different) twin prime pairs.at n=43A071348
- Square chains: the number of permutations (reversals not counted as different) of the numbers 1 to n such that the sum of any two consecutive numbers is a square.at n=19A071983
- Partition the concatenation 1234567... of natural numbers into successive strings which are multiples of 3 all different and > 3. (0 never taken as the most significant digit.)at n=24A077296
- a(n) = 101*n + 1.at n=40A078787