7182
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 32
- Divisor Sum
- 19200
- Proper Divisor Sum (Aliquot Sum)
- 12018
- 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
- 1944
- Möbius Function
- 0
- Radical
- 798
- Omega Function (Ω)
- 6
- Little Omega Function (ω)
- 4
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
- 150
- 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
- a(n) = floor(n(n-1)(n-2)(n-3)/20).at n=21A011930
- Numbers k such that k divides 2^(k+1) - 2.at n=29A014741
- Positive integers n such that n | (2^n + n/2 - 1).at n=27A015942
- Expansion of 1/((1-x)(1-7x)(1-8x)(1-11x)).at n=3A024439
- s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (Fibonacci numbers), t = (Lucas numbers).at n=13A025079
- Second 10-gonal (or decagonal) numbers: n*(4*n+3).at n=42A033954
- Write cosec x = 1/x + Sum e_n x^(2n-1)/(2n-1)!; sequence gives denominators of e_n.at n=8A036283
- Base 5 digits are, in order, the first n terms of the periodic sequence with initial period 2,1,2.at n=5A037570
- Triangular matrix arising in enumeration of catafusenes, read by rows.at n=49A038763
- Concatenation of the first n decimal digits of e-2.at n=3A039920
- a(n)=(s(n)+3)/10, where s(n)=n-th base 10 palindrome that starts with 7.at n=40A043086
- Number of nonnegative solutions of x1^2 + x2^2 + ... + x9^2 = n.at n=21A045851
- Consider all integer triples (i,j,k), j >= k > 0, with binomial(i+2,3)=j^3+k^3, ordered by increasing i; sequence gives k values.at n=15A054207
- Number of asymmetric types of (3,n)-hypergraphs without isolated nodes, under action of symmetric group S_3; asymmetric n-covers of an unlabeled 3-set.at n=9A055538
- Numbers k such that sigma(x) = k has exactly 6 solutions.at n=34A060662
- Determinant of the n X n matrix whose element (i,j) equals the |i-j|-th prime or if i=j, 0.at n=9A071079
- Expansion of (1+x^4*C^2)*C^4, where C = (1-(1-4*x)^(1/2))/(2*x) is g.f. for Catalan numbers, A000108.at n=7A071749
- Numbers k such that tau(k) = sigma(sopf(k)).at n=37A075867
- Triangle of generalized Chebyshev coefficients.at n=40A080419
- a(n) = (n+1)*(n+2)*(n+3)*(n+4)*(n+15)*3^n/360.at n=4A080423