4157
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 4158
- 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
- 4156
- Möbius Function
- -1
- Radical
- 4157
- 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
- 64
- Smith Number
- no
- Vampire 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
- 572
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Coordination sequence T1 for Zeolite Code RTE.at n=44A009890
- Twelve iterations of Reverse and Add are needed to reach a palindrome.at n=23A015993
- Numbers k such that the continued fraction for sqrt(k) has period 25.at n=13A020364
- a(n) = (d(n)-r(n))/5, where d = A026043 and r is the periodic sequence with fundamental period (0,2,3,0,0).at n=36A026045
- Square root of A030693.at n=11A030694
- Number of partitions of n into parts not of the form 9k, 9k+4 or 9k-4. Also number of partitions with at most 3 parts of size 1 and differences between parts at distance 3 are greater than 1.at n=37A035943
- Primes with first digit 4.at n=41A045710
- Discriminants of real quadratic fields with class number 1 and related continued fraction period length of 9.at n=17A050958
- Numbers n such that n^2 contains exactly 8 different digits.at n=11A054036
- Triangle read by rows: semigroups of order n with k idempotents, considered to be equivalent when they are isomorphic or anti-isomorphic (by reversal of the operator).at n=18A058123
- Numbers k such that the smoothly undulating palindromic number (35*10^k - 53)/99 is a prime.at n=5A062218
- Smallest prime whose decimal expansion ends (nontrivially) with the n-th prime; or 0 if no such prime exists.at n=36A065112
- Numbers which need 12 'Reverse and Add' steps to reach a palindrome.at n=23A065217
- Numbers k such that sigma(k+2) - sigma(k) = prime(k+1) - prime(k).at n=15A067062
- a(1)=1; a(n) = a(n-1) + [sum of all decimal digits present so far in the sequence].at n=29A072921
- Define the composite field of a prime q to be f(q) = (t,s) if p, q, r are three consecutive primes and q-p = t and r-q = s. This is a sequence of primes q with field (4,2).at n=37A073649
- a(1) = 1, a(n) = prime obtained as a partial sum of A073856.at n=5A073857
- Primes p such that the number of distinct prime divisors of all composite numbers between p and the next prime is 4.at n=36A075584
- Numbers k such that (k!! + (k+1)!! - 1)/2 is prime.at n=14A076209
- First prime in n-th group in A077280.at n=5A077282