7813
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
- 8428
- Proper Divisor Sum (Aliquot Sum)
- 615
- 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
- 7200
- Möbius Function
- 1
- Radical
- 7813
- 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
- 39
- 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
- Pseudoprimes to base 5.at n=16A005936
- Self-convolution of Pell numbers (A000129).at n=10A006645
- Largest number not the sum of distinct n-th-order polygonal numbers.at n=28A007419
- Pseudoprimes to base 24.at n=31A020152
- Strong pseudoprimes to base 5.at n=4A020231
- Strong pseudoprimes to base 25.at n=8A020251
- Numbers k such that the continued fraction for sqrt(k) has period 56.at n=36A020395
- Lucky numbers with size of gaps equal to 14 (lower terms).at n=39A031896
- Sums of distinct powers of 6.at n=37A033043
- a(n) = (5^n + 1)/2.at n=6A034478
- a(n) = ceiling((n^3)/2).at n=25A036486
- Positive numbers having the same set of digits in base 2 and base 6.at n=33A037411
- Sums of 3 distinct powers of 6.at n=11A038479
- T(n,n-1), array T as in A047110.at n=8A047113
- Becomes prime or 4 after exactly 8 iterations of f(x) = sum of prime factors of x.at n=25A048130
- Thickened cube numbers: a(n) = n*(n^2 + (n-1)^2) + (n-1)*2*n*(n-1).at n=12A050492
- Triangle of partial row sums of triangle A054446(n,m), n >= m >= 0.at n=46A054448
- Convolution triangle of A000129(n) (Pell numbers).at n=46A054456
- Prefixing, suffixing or inserting a 7 in the number anywhere gives a prime.at n=46A069832
- Sum of the reverses of the first n primes.at n=36A071602