919
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- yes
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 920
- Proper Divisor Sum (Aliquot Sum)
- 1
- 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
- 918
- Möbius Function
- -1
- Radical
- 919
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- 129
- Smith Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 157
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Names
- German
- neunhundertneunzehn· ordinal: neunhundertneunzehnste
- English
- nine hundred nineteen· ordinal: nine hundred nineteenth
- Spanish
- novecientos diecinueve· ordinal: 919º
- French
- neuf cent dix-neuf· ordinal: neuf cent dix-neufième
- Italian
- novecentodiciannove· ordinal: 919º
- Latin
- nongenti undeviginti· ordinal: 919.
- Portuguese
- novecentos e dezenove· ordinal: 919º
Appears in sequences
- Number of partitions of n, with two kinds of 1, 2, 3 and 4.at n=12A000710
- Primes p of the form 3k+1 such that Sum_{x=1..p} cos(2*Pi*x^3/p) > sqrt(p).at n=39A000921
- Numbers beginning with letter 'n' in English.at n=31A000981
- Primes with 7 as smallest primitive root.at n=8A001126
- Primes p such that the multiplicative order of 2 modulo p is (p-1)/6.at n=6A001136
- Cyclic numbers: 10 is a quadratic residue modulo p and class of mantissa is 2.at n=50A001914
- Palindromic primes: prime numbers whose decimal expansion is a palindrome.at n=18A002385
- Cuban primes: primes which are the difference of two consecutive cubes.at n=10A002407
- Max_{k=0..n} { Number of partitions of n into exactly k parts }.at n=32A002569
- Hex (or centered hexagonal) numbers: 3*n*(n+1)+1 (crystal ball sequence for hexagonal lattice).at n=17A003215
- Nonsquare values of m in the discriminant D = 4*m leading to a new maximum of the L-function of the Dirichlet series L(1) = Sum_{k>0} Kronecker(D,k)/k.at n=19A003421
- Absolute primes (or permutable primes): every permutation of the digits is a prime.at n=20A003459
- Numbers that are a sum of distinct positive cubes in more than one way.at n=29A003998
- Divisible only by primes congruent to 4 mod 5.at n=40A004618
- Prime-indexed primes: primes with prime subscripts.at n=36A006450
- Primes of form x^3 + y^3 + z^3 where x,y,z > 0.at n=28A007490
- Primes whose reversal in base 10 is also prime (called "palindromic primes" by David Wells, although that name usually refers to A002385). Also called reversible primes.at n=47A007500
- Primes of the form 8n+7, that is, primes congruent to -1 mod 8.at n=39A007522
- Expansion of (1+x^2)/((1-x)^2*(1-x^3)).at n=51A007980
- Coordination sequence T2 for Zeolite Code AEL.at n=20A008005