1978
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 25
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 3168
- Proper Divisor Sum (Aliquot Sum)
- 1190
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 924
- Möbius Function
- -1
- Radical
- 1978
- Omega Function (Ω)
- 3
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 50
- 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
- a(0) = 1, a(1) = 0, a(2) = -1; for n >= 3, a(n) = - a(n-2) + Sum_{ primes p with 3 <= p <= n} a(n-p).at n=57A002121
- Number of positions that the 3 X 3 X 3 Rubik cube puzzle can be in after exactly n moves, up to equivalence under the full group of order 48 of the cube and with a half-turn is considered to be 2 moves.at n=5A005452
- Coordination sequence T3 for Zeolite Code DFO.at n=34A009877
- Numbers k such that phi(k + 12) | sigma(k) for k not congruent to 0 (mod 3).at n=16A015850
- Numbers k such that the continued fraction for sqrt(k) has period 28.at n=35A020367
- Place where n-th 1 occurs in A007337.at n=47A022777
- T(2n,n+4), T given by A026769.at n=4A026886
- a(n) = Sum_{k=0..n-3} T(n,k) * T(n,k+3), with T given by A026626.at n=4A026964
- a(n) = diagonal sum of left-justified array T given by A027052.at n=22A027069
- Sequence satisfies T^2(a)=a, where T is defined below.at n=44A027589
- a(n) = n*(n+3).at n=43A028552
- Expansion of (theta_3(z)*theta_3(23z) + theta_2(z)*theta_2(23z))^3.at n=36A028659
- Numbers having period-2 7-digitized sequences.at n=40A031202
- Numbers with the property that all pairs of consecutive base-5 digits differ by more than 2.at n=33A032982
- Coordination sequence T2 for Zeolite Code TSC.at n=37A033617
- Number of partitions of n into parts not of the form 23k, 23k+5 or 23k-5. Also number of partitions with at most 4 parts of size 1 and differences between parts at distance 10 are greater than 1.at n=26A035993
- a(n) = prime(n)*prime(n+1) - prime(n).at n=13A037166
- Positive numbers having the same set of digits in base 8 and base 9.at n=18A037441
- Even numbers k such that b(k) is greater than b(k-1) and b(k+1); b(k) = A033178(k).at n=29A038007
- Base-5 palindromes that start with 3.at n=16A043008