6640
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 20
- Divisor Sum
- 15624
- Proper Divisor Sum (Aliquot Sum)
- 8984
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 2624
- Möbius Function
- 0
- Radical
- 830
- Omega Function (Ω)
- 6
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 137
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = n*(13*n - 1)/2.at n=32A022270
- Numbers whose base-5 representation contains exactly three 0's and two 3's.at n=18A045201
- a(n)=Sum{T(n,j): j=1,2,...,n}, array T given by A048212.at n=20A048222
- Numbers n such that n^1024 + 1 is prime (a generalized Fermat prime).at n=11A057002
- Engel expansion of 1/e = 0.367879... .at n=40A059193
- Numbers k such that phi(x) = k has exactly 9 solutions.at n=33A060672
- Floor(|x*sin(x)|)-perfect numbers, where f-perfect numbers for an arithmetical function f are defined in A066218.at n=9A066245
- Positions of A080313 in A014486.at n=22A080312
- Numbers k for which the sums of prime factors (ignoring multiplicity) of sigma(k) and phi(k) are equal but the sets of prime factors of sigma and phi are different.at n=24A081378
- Maximal number of segments (equivalently, corners) in a rook circuit of a 2n X 2n board.at n=41A085622
- Numbers n such that n and n+1 both are members of A074997; i.e., on the one hand n-1 and n+1 have the same prime signature, on the other hand n and n+2 have the same prime signature.at n=39A086540
- Duplicate of A057002.at n=11A088360
- XOR difference triangle of the powers of 3, read by rows.at n=40A099887
- Numbers n such that every digit of both n and n^2 contains a loop (only digits 0,4,6,8,9 in n and n^2).at n=11A107626
- Convolution of 4^n*n! and n!.at n=4A110467
- Number of permutations of length n which avoid the patterns 1432, 2134, 4132; or avoid the patterns 3124, 4123, 4321.at n=8A116773
- a(n) = n*(n+1)*(11*n+1)/6.at n=15A132112
- Numbers k such that k and k^2 use only the digits 0, 4, 6, 8 and 9.at n=12A136956
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (-1, 0, 0), (0, 1, -1), (1, -1, 0), (1, 1, 0)}.at n=8A149180
- a(n) = 512*n - 16.at n=12A157447