1278
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 2808
- Proper Divisor Sum (Aliquot Sum)
- 1530
- 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
- 420
- Möbius Function
- 0
- Radical
- 426
- Omega Function (Ω)
- 4
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 132
- 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
- Narayana's cows sequence: a(0) = a(1) = a(2) = 1; thereafter a(n) = a(n-1) + a(n-3).at n=20A000930
- Bisection of A000930.at n=10A002478
- Self numbers divisible by sum of their digits (or, self numbers which are also Harshad numbers).at n=32A003219
- a(n) = 1000*log_10(n) rounded down.at n=18A004225
- a(n) = round(n*phi^7), where phi is the golden ratio, A001622.at n=44A004942
- a(n) = ceiling(n*phi^7), where phi is the golden ratio, A001622.at n=44A004962
- Number of strict 7th-order maximal independent sets in path graph.at n=47A007386
- Some permutation of digits is a cube.at n=50A007939
- Noncubes such that some permutation of digits is a cube.at n=40A007940
- Coordination sequence T3 for Zeolite Code AEI.at n=27A008003
- Coordination sequence T1 for Zeolite Code AFT.at n=27A008026
- Coordination sequence T2 for Zeolite Code NAT.at n=24A008204
- If a, b in sequence, so is a*b+2.at n=46A009299
- Average of twin prime pairs.at n=42A014574
- a(n) = n^2 - floor( n/2 ).at n=36A014848
- Fibonacci sequence beginning 2, 22.at n=10A022373
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = A023532, t = A001950 (upper Wythoff sequence).at n=40A024374
- s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n-k+1), where k = [ n/2 ], s = A001950 (upper Wythoff sequence).at n=11A025122
- a(n) = (1/s(1) + 1/s(2) + ... + 1/s(n+1)) * LCM{1, 2, ..., n}, where s(k) = LCM{1,2,...,k}/k = A002944(k).at n=7A025537
- a(n) = Sum_{k=0..floor(n/2)} T(n,k), T given by A026758.at n=10A026766