7720
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
- 16
- Divisor Sum
- 17460
- Proper Divisor Sum (Aliquot Sum)
- 9740
- 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
- 3072
- Möbius Function
- 0
- Radical
- 1930
- Omega Function (Ω)
- 5
- 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
- 26
- 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
- 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 43.at n=27A031541
- Main diagonal of A082228.at n=44A082231
- a(n) = (5/6)*n^3+(5/2)*n^2+(8/3)*n.at n=20A092185
- a(0) = a(1) = 1; for n >= 2, a(n) = a(n-1) + a(n-2) - (n-1) if that number is positive and not already in the sequence, otherwise a(n) = a(n-1) + a(n-2) + (n-1).at n=21A117822
- Numbers k such that k^2 divides 9^k - 1.at n=29A127101
- Least positive power of 3 having exactly n consecutive 1's in its decimal representation.at n=7A131552
- Number of distinct values of Product_{p is in P} (m(p,P)+1) where m(p,P) is the multiplicity of part p in partition P, when P ranges over all partitions of n.at n=56A140312
- 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, 0, 0), (0, -1, 1), (0, 1, 0), (1, -1, 1), (1, 1, -1)}.at n=8A148901
- Number of rooted forests with n nodes in which each component contains at least two nodes.at n=12A174145
- Numbers k such that k^3 divides 9^(k^2) - 1.at n=46A177909
- Binomial transform of odd primes.at n=9A178167
- Number of n X n symmetric 0..3 arrays with each element equal to at least one horizontal or vertical neighbor, containing at least one 3 and with new values 0..3 introduced in lower triangular row major order.at n=4A192766
- a(n) is the smallest m for which 3^m contains n consecutive identical digits.at n=7A215727
- a(n) is the least value of k such that the decimal expansion of n^k contains eight or more consecutive identical digits.at n=1A217163
- Number of pairs of functions f, g from a size n set into itself satisfying f(g(f(x))) = g(f(f(x))).at n=4A239770
- The number of P-positions in the game of Nim with up to 4 piles, allowing for piles of zero, such that the number of objects in each pile does not exceed n.at n=21A241522
- Four times the sum of all divisors of all positive integers <= n.at n=47A243980
- Convolution of Fibonacci numbers (A000045) and partition numbers (A000041).at n=16A275388
- Number of subsets of {1,..,n} of cardinality >= 2 such that the elements of each counted subset are pairwise coprime.at n=22A276187
- a(n) = 12*n^2 + 10*n - 30.at n=25A277982