7553
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
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 9408
- Proper Divisor Sum (Aliquot Sum)
- 1855
- 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
- 5904
- Möbius Function
- -1
- Radical
- 7553
- 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
- 132
- 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 immersions of oriented circle into oriented sphere with n double points.at n=7A008986
- Distinct odd elements in 3-Pascal triangle A028262 (by row).at n=35A028268
- Odd elements (greater than 1) to right of central elements in 3-Pascal triangle A028262.at n=34A028274
- Numbers k such that k divides the (left) concatenation of all numbers <= k written in base 15 (most significant digit on right and removing all least significant zeros before concatenation).at n=11A029532
- Near Cullen numbers: k such that (k+1)*2^k + 1 is prime.at n=20A029544
- Quasi-Carmichael numbers to base -7: squarefree composites n such that prime p|n ==> p+7|n+7.at n=5A029567
- Hyperbinomial transform of A088957. Also the row sums of triangle A089460, which lists the coefficients for the second hyperbinomial transform.at n=5A089461
- Number of base 21 circular n-digit numbers with adjacent digits differing by 1 or less.at n=7A124714
- Square array A(n,m), n>=0, m>=0, read by antidiagonals: A(n,m) = n-th number of the m-th iteration of the hyperbinomial transform on the sequence of 1's.at n=33A144303
- Second bisection of A061041: a(n) = A061041(2n+1) = (2*n+1)*(2*n+9).at n=41A145923
- (Average of twin balanced prime pairs)/10.at n=24A173893
- Fibonacci sequence beginning 12, 25.at n=13A186620
- Increasing sequence generated by these rules: a(1)=1, and if x is in a then 3x+2 and 4x-3 are in a.at n=45A191139
- Floor-Sqrt transform of large Fine numbers (A000957).at n=18A192675
- a(n) = 384*n + 257.at n=19A229855
- Irregular triangle read by rows: T(n,k) = number of independent vertex subsets of size k of the graph g_n obtained by attaching two pendant edges to each vertex of the path graph P_n (having n vertices).at n=54A235116
- Irregular triangle read by rows: T(n,k) = number of independent vertex subsets of size k of the graph g_n obtained by attaching two pendant edges to each vertex of the path graph P_n (having n vertices).at n=58A235116
- Quasi-Carmichael numbers to at least one positive base.at n=39A259283
- Triangle read by rows: T(n,g) = number of general immersions of a circle with n crossings in a surface of arbitrary genus g, in the case that the circle is oriented and the surface is oriented.at n=21A260285
- a(n+1) = a(n) + (largest palindrome in decimal representation of a(n)), a(0) = 1.at n=45A262224