857
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 858
- 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
- 856
- Möbius Function
- -1
- Radical
- 857
- 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
- 28
- Smith Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- yes
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 148
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Names
- German
- achthundertsiebenundfünfzig· ordinal: achthundertsiebenundfünfzigste
- English
- eight hundred fifty-seven· ordinal: eight hundred fifty-seventh
- Spanish
- ochocientos cincuenta y siete· ordinal: 857º
- French
- huit cent cinquante-sept· ordinal: huit cent cinquante-septième
- Italian
- ottocentocinquantasette· ordinal: 857º
- Latin
- octingenti quinquaginta septem· ordinal: 857.
- Portuguese
- oitocentos e cinquenta e sete· ordinal: 857º
Appears in sequences
- Primes with 3 as smallest primitive root.at n=35A001123
- Lesser of twin primes.at n=33A001359
- Numbers k such that phi(k+2) = phi(k) + 2.at n=52A001838
- Full reptend primes: primes with primitive root 10.at n=51A001913
- Class numbers associated with terms of A001986.at n=21A001987
- Numbers that are the sum of 7 positive 5th powers.at n=25A003352
- Numbers that are the sum of 3 nonzero 6th powers.at n=6A003359
- a(1) = 1; for n>1, a(n) = a(n-1) + 1 + sum of distinct prime factors of a(n-1) that are < a(n-1).at n=39A003508
- Primes of the form 2^a + 3^b.at n=31A004051
- Divisible only by primes congruent to 3 mod 7.at n=51A004621
- Numbers divisible only by primes congruent to 1 mod 8.at n=34A004625
- Numbers that are the sum of at most 3 nonzero 6th powers.at n=15A004854
- Numbers that are the sum of at most 4 nonzero 6th powers.at n=22A004855
- Numbers that are the sum of at most 5 nonzero 6th powers.at n=30A004856
- Numbers that are the sum of at most 6 nonzero 6th powers.at n=39A004857
- Class 3+ primes (for definition see A005105).at n=51A005107
- Class 4- primes (for definition see A005109).at n=18A005112
- Number of partitions of n with at least 1 odd and 1 even part.at n=22A006477
- Long period primes: the decimal expansion of 1/p has period p-1.at n=52A006883
- Primes with both 10 and -10 as primitive root.at n=25A007349