7875
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
- 24
- Divisor Sum
- 16224
- Proper Divisor Sum (Aliquot Sum)
- 8349
- 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
- 3600
- Möbius Function
- 0
- Radical
- 105
- 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
- yes
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- yes
- 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
- 127
- 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
- a(n) = (5^n + 5^floor(n/2))/2.at n=6A001447
- Odd abundant numbers (odd numbers m whose sum of divisors exceeds 2m).at n=15A005231
- Number of increasing sequences of Goldbach type of length n; a(0) = 1 by convention.at n=8A008932
- a(n) = (2*n+1)*(4*n+1).at n=31A014634
- Number of ternary search trees on n keys.at n=11A019497
- Expansion of Product (1-m*q^m)^-15; m=1..infinity.at n=4A022739
- "AGK" (ordered, elements, unlabeled) transform of 2,1,1,1,...at n=19A032024
- Number of reversible strings with n beads of 5 colors.at n=6A032122
- Triangular numbers that have some nontrivial permutation of digits which is also triangular.at n=33A034291
- Numbers that are divisible by 5 and are the difference between two (different positive) cubes in at least one way.at n=34A038853
- Numbers ending with '5' that are the difference of two positive cubes.at n=24A038860
- Minimal elements of pairs of "Super Unitary Amicable Numbers", sorted by their minimal elements.at n=25A045613
- a(1)=6; if n = Product p_i^e_i, n>1, then a(n) = Product p_{i+1}^e_i * Product p_{i+2}^e_i.at n=11A045969
- Odd numbers divisible by exactly 6 primes (counted with multiplicity).at n=24A046319
- Number of nonempty subsets of {1,2,...,n} in which exactly 4/5 of the elements are <= (n-4)/2.at n=24A048068
- Triangle giving a(n,k) = number of (n,k) labeled Greg trees (n >= 2, 0 <= k <= n-2).at n=19A048159
- Numbers k such that 3^k == -1 (mod k-1).at n=12A055686
- Number of singular n X n (-1,0,1)-matrices.at n=3A057981
- McKay-Thompson series of class 25A for Monster.at n=26A058594
- 3 times pentagonal numbers: 3*n*(3*n-1)/2.at n=42A062741