16290
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
- 24
- Divisor Sum
- 42588
- Proper Divisor Sum (Aliquot Sum)
- 26298
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4320
- Möbius Function
- 0
- Radical
- 5430
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 4
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- yes
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 159
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = p*(p-1)/2 for p = prime(n).at n=41A008837
- T(n,n+1) + T(n,n+2) + ... + T(n,2n), T given by A027113.at n=8A027139
- Numbers whose base-5 representation has exactly 7 runs.at n=8A043607
- Coefficients of a special case of Poisson-Charlier polynomials.at n=58A046716
- Number of asymmetric types of (4,n)-hypergraphs under action of symmetric group S_4.at n=5A055537
- Triangular numbers whose index is a multiple of the sum of their digits.at n=31A067520
- Triangular numbers of the form 10*k.at n=36A069498
- Roman numerals for n evaluated as if in Sallows' base 27.at n=6A073427
- Smallest multiple of (n+1)-st prime which is == 1 mod n-th prime.at n=40A073604
- Triangular numbers which are the sum of two squares.at n=27A073613
- Triangular numbers which are 5-almost primes.at n=38A076579
- Third row of Pascal-(1,6,1) array A081581.at n=26A081591
- a(n) = p(n)*(p(n)-1)/2 where p(n) = upper member of n-th pair of twin primes.at n=12A082669
- a(n) = smallest k where (10^k+1)=0 mod prime(n)^2, or 0 if no such k exists.at n=41A086981
- Direct matrix (non-recursive) content of -n to n+1 symmetry matrices.at n=49A105110
- Least triangular number divisible by n-th prime.at n=41A112456
- Triangular numbers whose digit reversal is a powerful(1) number (A001694).at n=3A115692
- Triangular numbers equal to the difference between a prime number and its index.at n=31A115887
- Triangular numbers for which the sum of the digits is a heptagonal number.at n=21A117312
- Triangular numbers that can be written as sum of three positive cubes.at n=35A119977