1379
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 1584
- Proper Divisor Sum (Aliquot Sum)
- 205
- 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
- 1176
- Möbius Function
- 1
- Radical
- 1379
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 127
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- no
- Odd
- yes
Appears in sequences
- Central polygonal numbers (the Lazy Caterer's sequence): n(n+1)/2 + 1; or, maximal number of pieces formed when slicing a pancake with n cuts.at n=52A000124
- The convergent sequence A_n for the ternary continued fraction (3,1;2,2) of period 2.at n=11A000962
- a(n) = n*(n^2 + 1)/2.at n=14A006003
- Cald's sequence: a(n+1) = a(n) - prime(n) if that value is positive and new, otherwise a(n) + prime(n) if new, otherwise 0; start with a(1)=1.at n=91A006509
- Coordination sequence T1 for Zeolite Code MEL.at n=24A008150
- a(0) = 1, a(n) = 17*n^2 + 2 for n>0.at n=9A010007
- Numbers k such that k | 6^k + 1.at n=5A015953
- Cycle class sequence c(2n) (the number of true cycles of length 2n in which a certain node is included) for zeolite VFI = VPI-5 [ Al18P18O72 ]. 42 H2O.at n=4A019063
- Coordination sequence T2 for Zeolite Code SAO.at n=29A019572
- Numbers k such that the continued fraction for sqrt(k) has period 18.at n=42A020357
- a(n) = least m such that if r and s in {1/1, 1/3, 1/5,..., 1/(2n-1)} satisfy r < s, then r < k/m < s for some integer k.at n=30A024819
- a(n) = least m such that if r and s in {1/1, 1/2, 1/3, ..., 1/n} satisfy r < s, then r < k/m < (k+1)/m < s for some integer k.at n=28A024833
- a(n) = least m such that if r and s in {1/2, 1/4, 1/6, ..., 1/(2*n)} satisfy r < s, then r < k/m < (k+3)/m < s for some integer k.at n=13A024845
- Numbers that are the sum of 3 nonzero squares in exactly 8 ways.at n=47A025328
- Numbers that are the sum of 3 distinct nonzero squares in exactly 8 ways.at n=37A025346
- Square of the lower triangular normalized partition matrix.at n=41A027516
- An "extremely strange sequence": a(n+1) = [ A*a(n)+B ]/p^r, where p^r is the highest power of p dividing [ A*a(n)+B ] and p=2, A=4.001, B=1.2.at n=41A028948
- [ exp(13/20)*n! ].at n=5A030854
- Nonprime; becomes prime if any digit is deleted (zeros not allowed in the number).at n=28A034304
- Dropping any digit gives a prime number.at n=49A034895