17020
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 10
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 38304
- Proper Divisor Sum (Aliquot Sum)
- 21284
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6336
- Möbius Function
- 0
- Radical
- 8510
- 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
- 203
- 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) = 1*t(n) + 2*t(n-1) + ... + k*t(n+1-k), where k=floor((n+1)/2) and t(n)=2*n+1 (odd numbers).at n=45A023865
- a(n) = s(1)*t(n) + s(2)*t(n-1) + ... + s(k)*t(n-k+1), where k = floor(n/2), s = natural numbers, t = odd natural numbers.at n=44A024862
- Triangular numbers with sum of digits = 10.at n=24A068129
- Triangular numbers of the form 10*k.at n=37A069498
- Triangular numbers whose digit permutations yield at least two further triangular numbers.at n=11A069674
- Triangular numbers with property that swapping first and last digits also gives a triangular number.at n=39A069708
- a(1) = 0, then smallest triangular number such that a(n+1)- a(n) is a palindrome.at n=22A075057
- Products of members of pairs in A075333.at n=31A075337
- Smaller of the two successive triangular numbers which differ in the use of only one digit.at n=33A077759
- Least triangular number whose digit permutations yield exactly n further triangular numbers.at n=3A095870
- Triangle, read by rows, of the coefficients of [x^k] in G100228(x)^n such that the row sums are 4^n-1 for n>0, where G100228(x) is the g.f. of A100228.at n=42A100229
- Triangular numbers equal to the sum of a prime number with its index.at n=15A115886
- Heights of right triangles that are solutions to Leech's problem A117319.at n=40A117321
- Triangular numbers that can be written as sum of three positive cubes.at n=36A119977
- Triangular numbers that are the sums of five consecutive triangular numbers.at n=2A131557
- a(n) = n*(n+1)*(8*n + 1)/6.at n=23A132124
- Triangular numbers n*(n+1)/2 with n and n+1 composite, where number of prime factors in n > number of prime factors in n+1.at n=34A144523
- a(n) = 1000*n + 20.at n=16A157510
- Multiples of 23 whose digit reversal - 1 is also a multiple of 23.at n=29A166400
- Triangular numbers T from A000217 such that (4*T+1)/13 is prime.at n=11A208294