397
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 398
- 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
- 396
- Möbius Function
- -1
- Radical
- 397
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 27
- 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
- 78
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Names
- German
- dreihundertsiebenundneunzig· ordinal: dreihundertsiebenundneunzigste
- English
- three hundred ninety-seven· ordinal: three hundred ninety-seventh
- Spanish
- trescientos noventa y siete· ordinal: 397º
- French
- trois cent quatre-vingt-dix-sept· ordinal: trois cent quatre-vingt-dix-septième
- Italian
- trecentonovantasette· ordinal: 397º
- Latin
- trecenti nonaginta septem· ordinal: 397.
- Portuguese
- trezentos e noventa e sete· ordinal: 397º
Appears in sequences
- Primes p of the form 3k+1 such that -sqrt(p) < sum_{x=1..p} cos(2*Pi*x^3/p) < sqrt(p).at n=12A000922
- Primes with 5 as smallest primitive root.at n=12A001124
- Table T(n,k) in which n-th row lists prime factors of 2^n + 1 (n >= 0), with repetition.at n=49A001269
- Pythagorean primes: primes of the form 4*k + 1.at n=36A002144
- Numbers k for which the rank of the elliptic curve y^2 = x^3 - k is 2.at n=54A002154
- Primes congruent to 1 or 2 modulo 4; or, primes of form x^2 + y^2; or, -1 is a square mod p.at n=37A002313
- Cuban primes: primes which are the difference of two consecutive cubes.at n=7A002407
- The game of Mousetrap with n cards: the number of permutations of n cards having at least one hit after 2.at n=6A002468
- Primes of the form 6m + 1.at n=36A002476
- Numbers k such that (k^2 + 1)/10 is prime.at n=38A002733
- Number of solutions to a linear inequality.at n=18A002797
- a(n) = nearest integer to n^(3/2).at n=54A002821
- Numbers that are the sum of 3 positive cubes.at n=52A003072
- a(n) = Sum_{k=0..n} binomial(n,k^2).at n=11A003099
- Hex (or centered hexagonal) numbers: 3*n*(n+1)+1 (crystal ball sequence for hexagonal lattice).at n=11A003215
- Divisors of 2^44 - 1.at n=10A003549
- Primes congruent to {3, 5, 6} mod 7.at n=40A003625
- Inert rational primes in Q(sqrt(-5)).at n=41A003626
- Primes congruent to {5, 7} mod 8.at n=41A003628
- Primes p == +- 3 (mod 8), or, primes p such that 2 is not a square mod p.at n=41A003629