7857
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 27
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 10
- Divisor Sum
- 11858
- Proper Divisor Sum (Aliquot Sum)
- 4001
- 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
- 5184
- Möbius Function
- 0
- Radical
- 291
- Omega Function (Ω)
- 5
- 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
- 101
- 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
- Numbers that are the sum of 2 positive 4th powers.at n=40A003336
- a(n) = a(n-1) + a(n-3), with a(0) = a(1) = 1, a(2) = 5.at n=22A011761
- Smallest positive number that can be written as sum of distinct Fibonacci numbers in n ways.at n=79A013583
- Triangle of numbers associated with Genocchi numbers.at n=23A014784
- Triangle of numbers associated with Genocchi numbers.at n=25A014784
- Sorted entries in triangle in A014784.at n=13A035003
- Number of partitions satisfying cn(2,5) <= cn(0,5) and cn(3,5) <= cn(0,5).at n=39A039863
- a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1, a(2) = 2, and a(3) = 4.at n=14A049912
- Coefficients of replicable function number 12b.at n=11A058490
- Numbers k such that the simple continued fraction for (1+1/k)^k contains k.at n=49A071527
- Numbers k such that gcd(k, reverse(k)) = 27 = 3^3, where reverse(x) = A004086(x).at n=24A072016
- a(n) = 6^n + 9^n.at n=4A074621
- Sums of members of groups in A076062.at n=24A076060
- Numbers that can be represented as j^4 + k^4, with 0 < j < k, in exactly one way.at n=33A088687
- Sum of the first n pairs of consecutive primes (for example, a(3) = (2+3) + (3+5) + (5+7) = 25).at n=43A102724
- Number of complete rulers with length n.at n=15A103295
- a(n) = least k such that either 6*k*M(n)-1 or 6*k*M(n)+1 or both is prime, where M(i)= i-th Mersenne prime.at n=29A145983
- Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 1010-1111-0010 pattern in any orientation.at n=13A146632
- Number of ways to place zero or more nonadjacent 0,0 1,0 2,0 3,1 3,2 4,3 5,3 6,3 polyhexes in any orientation on a planar nXnXn triangular grid.at n=7A155396
- Number of connected spanning subgraphs in 3 X n grid.at n=3A158453