15541
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 15542
- 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
- 15540
- Möbius Function
- -1
- Radical
- 15541
- 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
- 40
- 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
- 1813
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes p such that the multiplicative order of 2 modulo p is (p-1)/5.at n=37A001135
- Cubes written in base 9.at n=21A004639
- Primes that remain prime through 3 iterations of function f(x) = 5x + 8.at n=25A023286
- Primes that remain prime through 4 iterations of function f(x) = 5x + 8.at n=6A023316
- a(n) = Sum_{k=floor((n+2)/2)..n} T(n, k), T given by A026998.at n=12A027009
- Number of partitions of n that do not contain 10 as a part.at n=36A027344
- Numerator of Sum_{p prime, p-1|n} 1/p.at n=39A027759
- Numerator of sum_{p prime, p-1 divides 2*n} 1/p.at n=19A027761
- a(n) = T(n,n) + T(n,n+1) + ... + T(n,2n), T given by A027960.at n=12A027973
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 98 ones.at n=8A031866
- Numbers k such that 221*2^k+1 is prime.at n=34A032487
- Numerators of continued fraction convergents to sqrt(398).at n=4A041756
- Third term of strong prime 5-tuples: p(m-1)-p(m-2) > p(m)-p(m-1) > p(m+1)-p(m) > p(m+2)-p(m+1).at n=35A054810
- Numbers p from A001125 such that 2*p-3 is prime.at n=20A063939
- Partial sums of sequence (essentially A002378): 1, 2, 6, 12, 20, 30, 42, 56, 72, 90, ...at n=35A064999
- Primes of the form 2^i*3^j - (i+j) with i, j >= 0.at n=16A069356
- Primes of the form 210n + 1.at n=35A073102
- Primes associated with groups in A076077.at n=28A076076
- Numerators in the convergents of the continued fraction representation of (e-1)/(e+1).at n=4A086403
- Number of distinct lines through the origin in the n-dimensional lattice of side length 6.at n=5A090022