7770
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 32
- Divisor Sum
- 21888
- Proper Divisor Sum (Aliquot Sum)
- 14118
- 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
- 1728
- Möbius Function
- -1
- Radical
- 7770
- 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
- no
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- no
- Lucas Number
- no
- Tetrahedral Number
- yes
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 39
- 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
- Tetrahedral (or triangular pyramidal) numbers: a(n) = C(n+2,3) = n*(n+1)*(n+2)/6.at n=35A000292
- a(n) = 1^2 + 3^2 + 5^2 + 7^2 + ... + (2*n-1)^2 = n*(4*n^2 - 1)/3.at n=18A000447
- Stirling numbers of the second kind, S(n,4).at n=5A000453
- Largest Stirling numbers of second kind: a(n) = max_{k=1..n} S2(n,k).at n=8A002870
- Triangle of Stirling numbers of the second kind, S2(n,k), n >= 1, 1 <= k <= n.at n=39A008277
- Reflected triangle of Stirling numbers of 2nd kind, S(n,n-k+1), n >= 1, 1 <= k <= n.at n=41A008278
- Binomial coefficient C(37,n).at n=3A010953
- Binomial coefficient C(n,34).at n=3A010987
- Orders of cyclotomic polynomials containing a coefficient the absolute value of which is >= 5.at n=40A013593
- Weight distribution of [50,28,8] code associated with Hoffman-Singleton and Higman-Sims graphs.at n=5A015067
- Even tetrahedral numbers.at n=26A015220
- a(n) = T(n,n), T given by A026584. Also a(n) is the number of integer strings s(0), ..., s(n) counted by T, such that s(n)=0.at n=12A026585
- a(n) = self-convolution of row n of array T given by A026584.at n=6A027282
- (prime(n)-5)(prime(n)-7)(prime(n)-9)/48.at n=19A030002
- "AGJ" (ordered, elements, labeled) transform of 2,2,2,2,...at n=6A032014
- a(n) is the number of labeled rooted trees on a set of size n where each node has at most 4 neighbors that are further away from the root than the node itself.at n=6A036776
- Numbers having four 5's in base 6.at n=20A043392
- Numbers having three 7's in base 10.at n=21A043519
- Products of exactly 5 distinct primes.at n=14A046387
- Triangle of Stirling numbers of 2nd kind, S(n,k), n >= 0, 0 <= k <= n.at n=49A048993