7912
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 15840
- Proper Divisor Sum (Aliquot Sum)
- 7928
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- yes
- Untouchable Number
- no
- Primitive Abundant
- yes
Derived Values
- Euler's Totient
- 3696
- Möbius Function
- 0
- Radical
- 1978
- 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
- 52
- 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
- Primitive weird numbers: weird numbers with no proper weird divisors.at n=5A002975
- Cubes written backwards.at n=12A004165
- Weird numbers: abundant (A005101) but not pseudoperfect (A005835).at n=5A006037
- Numbers k such that sigma(k+2) = sigma(k).at n=17A007373
- Smallest positive number that can be written as sum of distinct Fibonacci numbers in n ways.at n=83A013583
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly nine 1's.at n=26A020445
- Base 7 digits are, in order, the first n terms of the periodic sequence with initial period 3,2,0.at n=4A037670
- a(n) = a(n-1) + a(m) for n >= 4, where m = 2^(p+1) + 2 - n 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=44A050053
- Numbers m such that m divides sigma(m) - d(m).at n=5A056075
- Number of hexagonal regions in regular n-gon with all diagonals drawn.at n=37A067153
- Duplicate of A056075.at n=5A070019
- Determinant of n X n matrix of form : [1 2 1 0 0 0 0 0 0 0 / 2 1 2 1 0 0 0 0 0 0 / 1 2 1 2 1 0 0 0 0 0 / 0 1 2 1 2 1 0 0 0 0 / 0 0 1 2 1 2 1 0 0 0 / 0 0 0 1 2 1 2 1 0 0 / 0 0 0 0 1 2 1 2 1 0 / 0 0 0 0 0 1 2 1 2 1 / 0 0 0 0 0 0 1 2 1 2 / 0 0 0 0 0 0 0 1 2 1].at n=14A071534
- Smallest k such that n^8+k^8, n^4+k^4, n^2+k^2, n+k are simultaneously prime.at n=6A071564
- Largest eigenvalue, rounded to the nearest integer, of a rank n matrix of 1..n^2 filled successively along antidiagonals (A069480).at n=23A072332
- Imaginary part of absolute Gaussian perfect numbers, in order of increasing magnitude.at n=21A102532
- Odd cubes written backwards and sorted.at n=9A107314
- Lesser of twin admirable numbers: k such that k and k+2 are both admirable numbers.at n=29A109730
- Number of ways to write n as an ordered sum of 1s, 2s, 3s and 4s such that no 2 precedes any 1 and no 3 precedes any 1 or 2.at n=23A123569
- Weird numbers (A006037) not divisible by 5.at n=2A138850
- Numbers n whose abundance is 16.at n=4A141547