7642
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
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 11466
- Proper Divisor Sum (Aliquot Sum)
- 3824
- 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
- 3820
- Möbius Function
- 1
- Radical
- 7642
- 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
- 31
- 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
- yes
- Odd
- no
Appears in sequences
- a(1)=1, a(n) = 19*a(n-1) + n.at n=3A014903
- Numbers k such that the continued fraction for sqrt(k) has period 39.at n=10A020378
- Number of partitions of n such that cn(0,5) = cn(2,5) < cn(3,5) = cn(4,5) <= cn(1,5).at n=60A036854
- Values of A038007 not ending in 6 or 8.at n=8A038009
- Values of A038007 ending in 2.at n=0A038011
- Number of amicable pairs where smaller term of the pair is less than 10^n.at n=11A066873
- Spiro-tetranacci numbers: a(n) = sum of four previous terms that are nearest when terms arranged in a spiral.at n=21A092369
- Numbers k such that phi(k)*sigma(k) is a triangular number.at n=12A115911
- Numbers k such that both k and the k-th prime have nonincreasing digits.at n=47A116067
- Numbers n such that 2^x + 3^y is never prime when max(x,y) = n.at n=11A159625
- Number of n X n 0..5 arrays with every row and column nondecreasing rightwards and downwards, and the number of instances of each value within one of each other.at n=3A201135
- Number of nX4 0..5 arrays with every row and column nondecreasing rightwards and downwards, and the number of instances of each value within one of each other.at n=3A201138
- T(n,k)=Number of nXk 0..5 arrays with every row and column nondecreasing rightwards and downwards, and the number of instances of each value within one of each other.at n=24A201142
- Number of distinct denominators of rational numbers whose continued fraction consists exclusively of 1s and 2s and has length <=n.at n=14A228805
- Semiprimes with digits in strictly decreasing order.at n=51A235108
- Number of partitions p of n such that the number of parts is not a part and max(p) - min(p) is a part.at n=41A241383
- Numbers k such that 1 + k + k^3 + k^5 + k^7 + k^9 + ... + k^49 is prime.at n=38A244388
- Number of length 3 0..n arrays with each partial sum starting from the beginning no more than one standard deviation from its mean.at n=26A244791
- T(n,k)=Number of length n+2 0..k arrays with no three consecutive terms having the sum of any two elements equal to twice the third.at n=46A248461
- Number of length 2+2 0..n arrays with no three consecutive terms having the sum of any two elements equal to twice the third.at n=8A248463