7256
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
- 8
- Divisor Sum
- 13620
- Proper Divisor Sum (Aliquot Sum)
- 6364
- 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
- 3624
- Möbius Function
- 0
- Radical
- 1814
- Omega Function (Ω)
- 4
- 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
- 57
- 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
- Number of partitions with no even part repeated; partitions of n in which no parts are multiples of 4.at n=37A001935
- Numbers k such that k, k+1, k+2 and k+3 have the same number of divisors.at n=5A006601
- Values of Zagier's function J_1.at n=9A027652
- Values of Zagier's function J_1(k) as k runs through the numbers -1, 0, 3, 4, 7, 8, ... which are == -1 or 0 mod 4.at n=5A027653
- Zagier's function J_1(4*n).at n=2A027655
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 21.at n=33A031519
- Sets of 4 consecutive numbers with equal number of divisors.at n=20A039665
- Nearest integer to (Product(n^((1 + log(1 + i))/(1 + i^2)), {i, 1, n})).at n=46A062493
- n*10^5-1, n*10^5-3, n*10^5-7 and n*10^5-9 are all prime.at n=1A064979
- Numbers k such that phi(k) divides (sigma(k+2) + sigma(k-2)).at n=41A067245
- Number of partitions of 2n+1 in which no parts are multiples of 4.at n=18A081056
- Even elements of A082931.at n=35A082933
- Number of nonempty subsets S of {1,2,3,...,n} that have the property that no element x of S is a nonnegative integer linear combination of elements of S-{x}.at n=21A103580
- Even numbers n such that n^2 is an arithmetic number.at n=30A107924
- Numbers n such that z(n) and z(n+1) are both prime, where z(n) = a^d + b^d + c^d + ..., where a*b*c* ... is the prime factorization of n and d is the largest digit of n.at n=9A109280
- Sequence is obtained from Catalan numbers (A000108) by taking the factorial of each digit and adding them up.at n=21A165163
- a(n)=(A210686(n)-1)/30.at n=36A181903
- Sums of least knight's moves from (0,0) to points in the square lattice [-n,n]x[-n,n].at n=16A183047
- Start with a(1) = 1, a(2) = 1, then a(n)*3^k = a(n+1) + a(n+2), with 3^k the smallest power of 3 (k>0) such that all terms a(n) are positive integers.at n=20A233525
- Expansion of (sqrt(8*x+4*sqrt(1-4*x)-3)-1)/(2*sqrt(1-4*x)-2).at n=9A243760