9870
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 32
- Divisor Sum
- 27648
- Proper Divisor Sum (Aliquot Sum)
- 17778
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 2208
- Möbius Function
- -1
- Radical
- 9870
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 5
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
- no
- Narcissistic Number
- no
- Collatz Steps
- 197
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- yes
- 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
- Aliquot sequence starting at 966.at n=8A014363
- Fibonacci sequence beginning 0, 10.at n=16A022093
- n written in fractional base 10/9.at n=30A024664
- a(n) = 2*n*(4*n + 1).at n=35A033585
- Products of exactly 5 distinct primes.at n=23A046387
- Numbers that are divisible by exactly 5 different primes.at n=32A051270
- a(n) is the smallest positive integer such that a(n)*(1^n + 2^n + ... + x^n) is a polynomial in x with integer coefficients.at n=46A064538
- Duplicate of A068804.at n=14A068709
- Triangular numbers whose digits can be rearranged to form a substring of 123456789012345678901234....at n=15A068804
- Triangular numbers with property that digits alternate in parity.at n=25A068882
- Largest n-digit triangular number with property that digits alternate in parity, or 0 if no such number exists.at n=3A068884
- Integers which have at least two different factorizations into coprime parts whose sum are equal.at n=43A069064
- Triangular numbers of the form 10*k.at n=28A069498
- Triangular numbers of the form 21*k.at n=26A069499
- Triangular numbers with arithmetic mean of digits = integer (sum of digits = A multiple of the number of digits).at n=42A069712
- Let omega(m) be the number of distinct prime divisors of m. Then a(n) is the largest n-digit squarefree number such that omega(n) > omega(j) for all j < n.at n=3A074112
- Triangular numbers which are 5-almost primes.at n=27A076579
- Triangular numbers with square pyramidal indices.at n=7A076767
- Positive integers not expressible as the sum of a prime and a triangular number.at n=57A076768
- a(1) = 1; for n > 1, a(n) = smallest triangular number which is n times another triangular number > 1, or -1 if no such number exists.at n=46A077672