15705
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 27300
- Proper Divisor Sum (Aliquot Sum)
- 11595
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8352
- Möbius Function
- 0
- Radical
- 5235
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 3
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
- 102
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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
- Lonely numbers: distance to closest prime sets a new record.at n=13A051650
- Smallest number at distance n from nearest prime.at n=22A051652
- Smallest number at distance 2n from nearest prime.at n=11A051728
- a(n) is the smallest number for which the prime distance A051699 is equal to n.at n=22A077019
- Least positive k such that the distance from k to closest prime = n.at n=22A079582
- Smallest k such that both k-n and k+n are primes and there are no primes between them.at n=22A087378
- A Chebyshev transform of Padovan numbers.at n=36A099491
- Smallest number at distance 2n from nearest prime (variant 2).at n=11A132860
- Smallest number at distance 2n from nearest prime (variant 3).at n=11A133490
- Numbers n such that the fractional part of (4/3)^n is less than 1/n.at n=6A154131
- First string of 43 consecutive composite numbers.at n=21A177949
- Total number of largest parts in all partitions of n that contain at least two distinct parts.at n=34A182629
- a(n) is the minimal k such that nextprime(2k+1) - 2k = prime(n) where nextprime(n) is least prime > n.at n=16A229512
- Numbers n for which the numbers 6n+1, 3n+2, 6n+7 are all odd composite squarefree numbers, but none are semiprimes.at n=22A263510
- a(n) is the smallest number m, such that m+n is the next prime and m-n is the previous prime.at n=21A282690
- 8*n analog to Keith numbers.at n=6A282763
- p-INVERT of the odd positive integers, where p(S) = 1 - S - 3 S^2.at n=6A292486
- List of indices where the maximum of {A316190(j) | j<=n} increases.at n=11A316191
- Triangle read by rows: Take a pentagon with all diagonals drawn, as in A331929. Then T(n,k) = number of k-sided polygons in that figure for k = 3, 4, ..., n+5.at n=40A331939
- Midpoints of record gaps between primes: a(n) = (A000101(n) + A002386(n))/2 for n > 1.at n=10A354604