7961
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 5
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 8400
- Proper Divisor Sum (Aliquot Sum)
- 439
- 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
- 7524
- Möbius Function
- 1
- Radical
- 7961
- Omega Function (Ω)
- 2
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 145
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- Squarefree Number
- yes
- 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
- From a nim-like game.at n=32A003412
- Numbers k such that the continued fraction for sqrt(k) has period 66.at n=38A020405
- a(n) = n*(11*n+1)/2.at n=38A022269
- The sequence M(n) in A022905.at n=26A022908
- Duplicate of A022269.at n=37A026817
- a(n) = (n - 1)*(n^2 + n - 1).at n=20A033445
- a(n) = (1/3!)*(n^3 + 24*n^2 + 107*n + 90), compare A059604.at n=29A059605
- Composite numbers whose divisors (except 1) all contain the digit 9.at n=9A062680
- Reflective numbers: k such that the decimal encoding of the prime factorization of k (A067599) is palindromic.at n=39A066985
- Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=1, r=5, I={0,1,4}.at n=39A079956
- Number of base 27 n-digit numbers with adjacent digits differing by three or less.at n=4A126495
- Numerator of Euler(n, 1/20).at n=4A156746
- a(n) = (2*n^3 + 5*n^2 + 21*n)/2.at n=18A162266
- a(n) = 5*n^2 - n + 1.at n=40A172043
- Smallest j such that j*2*p(n)^3-1=q is prime, j*2*p(n)*q^2-1=r, j*2*p(n)*r^2-1=s, where r and s are also prime.at n=23A224611
- Lexicographically earliest sequence whose second differences are the digits of Pi.at n=58A227844
- Number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 145", based on the 5-celled von Neumann neighborhood.at n=45A270286
- Numbers k such that the decimal number concat(4,k) is a square.at n=25A273359
- Solution of the complementary equation a(n) = 2*a(n-1) - a(n-3) + b(n-2), where a(0) = 1, a(1) = 3, a(2) = 5, b(0) = 2, b(1) = 4, b(2) = 6, and (a(n)) and (b(n)) are increasing complementary sequences.at n=14A295617
- Number of chordless cycles in the n-Fibonacci cube graph.at n=6A297668