7219
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
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 7220
- Proper Divisor Sum (Aliquot Sum)
- 1
- 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
- 7218
- Möbius Function
- -1
- Radical
- 7219
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- 44
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 923
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- a(n) = n^3 + n^2 - 1.at n=18A003777
- Oscillates under partition transform.at n=47A007210
- Primes of the form n^2 - 6.at n=15A028880
- 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 83.at n=33A031581
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 78 ones.at n=1A031846
- Number of partitions of n with equal nonzero number of parts congruent to each of 2 and 3 (mod 5).at n=43A035569
- Numbers whose base-4 representation contains exactly three 0's and three 3's.at n=21A045079
- Primes with first digit 7.at n=40A045713
- Discriminants of imaginary quadratic fields with class number 15 (negated).at n=28A046012
- First term of strong prime quintets: p(m+1)-p(m) > p(m+2)-p(m+1) > p(m+3)-p(m+2) > p(m+4)-p(m+3).at n=18A054808
- Primes of the form 4*k^2 + 163.at n=35A057604
- Numbers k such that 29^k - 28^k is prime.at n=1A062595
- Row sums in triangle A081994.at n=17A081997
- Primes p such that A001414(p-1) and A001414(p+1) are both prime, where A001414 = sum of primes dividing n (with repetition).at n=39A086715
- Primes which when concatenated with their reverse and incremented by 2 yield a new prime.at n=40A088883
- Primes p such that both prime(p) + prime(p+1) +/-1 are also primes.at n=35A093734
- Largest prime p such that the sum of n consecutive primes plus p is equal to (n+1)^3.at n=18A100572
- Beginning with 2, least prime not occurring earlier such that the concatenation of first n terms has the least prime factor prime(n).at n=17A100759
- Primes p equal to the sum of two successive sexy primes - 1 such that p - 6 is also prime.at n=16A104047
- Primes one less than the sum over a sexy prime pair.at n=49A104227