11719
domain: N
Properties
Digital Properties
- Digit Count
- 5
- 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
- 11720
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 11718
- Möbius Function
- -1
- Radical
- 11719
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 143
- 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
- yes
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1407
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Cuban primes: primes which are the difference of two consecutive cubes.at n=29A002407
- Number of paraffins.at n=36A005999
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 88 ones.at n=4A031856
- Numbers ending with '9' that are the difference of two positive cubes.at n=38A038864
- Sequence of 2 Pythagorean triangles, each with a leg and hypotenuse prime. The leg of the second triangle is the hypotenuse of the first.at n=36A048270
- Sequence of 3 Pythagorean triangles, each with a leg and hypotenuse prime. The hypotenuse of each triangle is the leg of the next triangle.at n=4A048295
- a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 4, where m = 2*n - 2 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = a(3) = 1.at n=17A049887
- Values of A (the short leg) of a Pythagorean triangle with A and C (the hypotenuse) both prime and part of a twin prime.at n=26A051642
- Primes p such that p, p+12, p+24 are consecutive primes.at n=8A052188
- Prime number spiral (clockwise, Northeast spoke).at n=19A054553
- Primes p such that x^31 = 2 has no solution mod p.at n=40A059225
- Primes on axis of Ulam square spiral (with rows ... / 7 8 9 / 6 1 2 / 5 4 3 / ... ) with origin at (1).at n=46A078784
- Square number array T(n,k) = (k*(k+2)^n+1)/(k+1) read by antidiagonals.at n=51A083064
- 4th row of number array A083064.at n=6A083065
- Number of distinct partitions of triangular numbers n*(n+1)/2 into 3 parts for n>=1.at n=26A104385
- Primes p such that p's set of distinct digits is {1,7,9}.at n=10A108384
- Numbers k such that sigma(k) plus the k-th prime is a triangular number.at n=32A115907
- Primes for which the weight as defined in A117078 is 23.at n=25A119504
- a(n) = prime(n^2 + n + 1).at n=37A122566
- Largest number k such that k^2 divides A007781(6n+1).at n=30A127854