15241
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 15242
- 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
- 15240
- Möbius Function
- -1
- Radical
- 15241
- 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
- 177
- 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
- 1779
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- a(n) = a(n-1) + a(n-4), starting 1,1,1,3.at n=30A014101
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted then there are a pair of central terms both equal to 8.at n=30A031421
- Primes p such that (p+1)/2 and (p+2)/3 are also primes.at n=34A036570
- Denominators of continued fraction convergents to sqrt(449).at n=9A041855
- Least prime in A031936 (lesser of 18-twins) whose distance to the next 18-twin is 2*n.at n=36A052358
- Primes which can be represented as the sum of a number and its reverse.at n=39A072382
- Numbers n for which there are exactly five k such that n = k + reverse(k).at n=33A072429
- Numbers n such that 3^n + 2^(n-1) is prime.at n=39A082103
- a(n) = floor(10^n/3^n).at n=8A094977
- Main diagonal of triangle A103284, in which row n+1 is formed by sorting, in ascending order, the result of the convolution of row n with {1,1}.at n=17A103285
- Numbers k such that the k-th triangular number contains only digits {1,5,6}.at n=27A119133
- Primes p such that p^2-p-1 and p^2-p+1 are twin primes.at n=34A120364
- Prime numbers p such that p +- ((p-1)/2) are primes.at n=33A137702
- Primes of the form x^2 + 840*y^2.at n=39A139665
- Primes congruent to 13 mod 47.at n=38A142364
- Primes congruent to 30 mod 53.at n=34A142560
- Primes congruent to 19 mod 59.at n=30A142746
- Primes congruent to 52 mod 61.at n=28A142850
- Primes congruent to 32 mod 67.at n=29A154621
- Primes p such that p^2 + 6, p^2 + 12 and p^2 + 18 are all prime.at n=10A173627