7391
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 7800
- Proper Divisor Sum (Aliquot Sum)
- 409
- 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
- 6984
- Möbius Function
- 1
- Radical
- 7391
- 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
- 207
- 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
- Expansion of 1/(1-x^10-x^11-x^12-x^13-x^14-x^15-x^16-x^17-x^18-x^19-x^20).at n=68A017896
- Numbers whose set of base-9 digits is {1,2}.at n=33A032930
- Numbers whose base-3 representation has exactly 9 runs.at n=5A043589
- Numbers n such that number of runs in the base 3 representation of n is congruent to 1 mod 8.at n=21A043799
- Numbers n such that number of runs in the base 3 representation of n is congruent to 0 mod 9.at n=5A043806
- Numbers k such that number of runs in the base 3 representation of k is congruent to 9 mod 10.at n=5A043824
- Composite numbers whose divisors (except 1) all contain the digit 9.at n=7A062680
- Semiprimes p1*p2 such that p2 mod p1 = 9, with p2 > p1.at n=36A064907
- Sum of terms in n-th group in A075352.at n=39A075356
- a(n) = smallest k such that the base 4 Reverse and Add! trajectory of A075421(n) joins the trajectory of k.at n=41A091676
- Sum of the right diagonal in ordered 3 X 3 prime squares.at n=40A105091
- Odd numbers n for which 13 is the smallest i (>= 1) with Jacobi symbol J(i,n) getting either a value 0 or -1.at n=21A112076
- Numbers m such that (1/99)*Sum_{k=1..m} k! = A007489(m)/99 is prime.at n=26A122990
- Number of base 19 circular n-digit numbers with adjacent digits differing by 4 or less.at n=4A125356
- Integers of the form sum_{i=2521..j} i/(i-2520) for any upper limit j.at n=9A144971
- a(n) = 3*A146085(n) - 1.at n=41A146087
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, -1), (-1, -1, 1), (0, 1, -1), (0, 1, 1), (1, 0, -1)}.at n=9A148625
- Multiples of 19 whose reversal + 1 is also a multiple of 19.at n=23A166392
- Partial sums of A006343.at n=10A176074
- Triangle of coefficients of polynomials v(n,x) jointly generated with A209999; see the Formula section.at n=48A210287