7977
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 30
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 10640
- Proper Divisor Sum (Aliquot Sum)
- 2663
- 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
- 5316
- Möbius Function
- 1
- Radical
- 7977
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 52
- 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
- Numbers k such that the continued fraction for sqrt(k) has period 62.at n=35A020401
- 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 58.at n=38A031556
- Number of n-step self-avoiding paths on the first octant of a 3-dimensional cubic lattice, starting at the origin.at n=7A039648
- Numbers having three 7's in base 10.at n=33A043519
- Arithmetic mean of largest subset of {A063676(1), ......., A063676(n-1)} such that a(n) is an integer and a(n) is maximal.at n=43A063678
- Prefixing, suffixing or inserting a 7 in the number anywhere gives a prime.at n=47A069832
- Tribonacci numbers: a(n) = a(n-1) + a(n-2) + a(n-3), with a(0) = 1, a(1) = 1, a(2) = 0.at n=17A081172
- Near-repdigit semiprimes with 7 as repeated digit.at n=21A105988
- Triangle read by rows: T(n,k) is number of paths from (0,0) to (3n,0) that stay in the first quadrant (but may touch the horizontal axis), consisting of steps u=(2,1), U=(1,2), or d=(1,-1) and having k U=(1,2) steps among the steps leading to the first d step.at n=23A108441
- Number of permutations of length n which avoid the patterns 2341, 4123, 4132.at n=8A116780
- Numbers of the form 56+p^2 (where p is a prime).at n=23A138690
- a(n) = (3*n^5 - 35*n^4 + 145*n^3 - 235*n^2 + 152*n + 30)/30.at n=12A161704
- Number of (n+1) X 7 binary arrays with every 2 X 2 subblock commuting with each of its horizontal and vertical 2 X 2 subblock neighbors.at n=9A186459
- Composite numbers and 1 which yield a prime whenever a 7 is inserted anywhere in them, including at the beginning or end.at n=31A216168
- Number of partitions p of n such that max(p)-min(p) = 5.at n=46A218568
- Number of 3 X n 0..1 arrays with diagonals and antidiagonals unimodal and rows nondecreasing.at n=21A223950
- Number of partitions of n such that m(greatest part) <= m(1), where m = multiplicity.at n=33A240077
- a(n) begins the first chain of 9 consecutive positive integers of h-values with symmetrical gaps about the center, where h(k) is the length of the finite sequence k, f(k), f(f(k)), ...., 1 in the Collatz (or 3x + 1) problem.at n=35A268288
- Decimal representation of the x-axis, from the left edge to the origin, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 419", based on the 5-celled von Neumann neighborhood.at n=13A282071
- Numbers whose smallest decimal digit is 7.at n=43A284068