7901
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
- 1
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 7902
- 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
- 7900
- Möbius Function
- -1
- Radical
- 7901
- 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
- 39
- 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
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- yes
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 998
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Number of simple perfect squared squares of order n up to symmetry.at n=28A006983
- Numbers n such that n, 2n+1, and 4n+3 all prime.at n=38A007700
- Numbers k such that the continued fraction for sqrt(k) has period 89.at n=7A020428
- Upper prime of a difference of 18 between consecutive primes.at n=33A031937
- Let a (resp. b,c,d) be number of primes in the range {2..p} that end in 1 (resp. 3,7,9); sequence gives p such that a=d and b=c.at n=41A038562
- Primes p from A031924 such that A052180(primepi(p)) = 7.at n=41A052231
- a(0)=1, a(1)=2, a(2)=5, a(n) = 3*a(n+2) - a(n+3).at n=9A052963
- Integers that can be expressed as the sum of consecutive primes in exactly 4 ways.at n=26A054999
- Initial primes of Cunningham chains of first type with length exactly 3. Primes in A059453 that survive as primes just two "2p+1 iterations", forming chains of exactly 3 terms.at n=20A059762
- Primes of form 100*k + 1.at n=24A062800
- Primes expressible as the sum of (at least two) consecutive primes in at least 3 ways.at n=13A067379
- a(1)=11; for n>1, a(n) is the smallest prime not occurring earlier beginning with a(n-1) without its first digit. Single-digit primes are not allowed unless they arise from the previous term as multi-digit number with leading zero(s) (i.e., a(n-1) has 0 as second digit) which are remembered for the subsequent left-truncations.at n=45A089755
- Numbers p such that p = (prime(n)+ prime(n+3))/2 is prime for prime indices n=2, 3, 5...at n=12A098039
- Primes of the form a^5 + b^3 with a,b>0.at n=15A100273
- Primes of the form 47n+5.at n=23A100760
- Primes from merging of 4 successive digits in decimal expansion of exp(Pi).at n=34A105009
- Prime numbers p such that p+6, p^2+6^2, p^4+6^4 are all primes.at n=7A107441
- Prime numbers p such that p+6 and p^2+6^2 are both primes.at n=34A107442
- Square-chain primes (including square-loop primes).at n=26A108659
- Cumulative sums of int(prime*e) which are primes.at n=7A117527