# Problems

1 – 50 of 101
 Problem Title Likes Solvers Difficulty

#### Problem 56260. Leonardo primes

Created by: Lenka Hanakova

3

19

#### Problem 248. Twins in a Window

Created by: Ned Gulley

Tags primes

2

151

#### Problem 42704. prime to each other

Created by: George-Felix Leu

Tags primes

1

58

#### Problem 44862. Ratio between sum of primes and sum of factors

Created by: Jesús Zambrano

0

29

#### Problem 52293. Palindromic Primes

Created by: Dyuman Joshi

3

17

#### Problem 47798. Check if the input is a balanced prime

Created by: Mehmet OZC

2

27

#### Problem 3020. Prime Letters = Removing

Created by: Gareth Thomas

Tags primes

1

91

#### Problem 51466. List prime anagrams of a number

Created by: ChrisR

1

18

#### Problem 43269. Get all prime factors

Created by: Jamil Kasan

6

633

#### Problem 1761. Primes Faster for Large N

Created by: Richard Zapor

1

53

#### Problem 42749. Find the nearest prime

Created by: Pooja Narayan

Tags math, primes

1

99

#### Problem 1298. P-smooth numbers

Created by: Richard Zapor

Tags primes, find, mod

1

85

#### Problem 43085. Primes Checker

Created by: Jamil Kasan

8

59

#### Problem 47808. Check if the input is an interprime

Created by: Mehmet OZC

1

21

#### Problem 50933. Find pairs of primes with the same digit sum

Created by: ChrisR

1

10

#### Problem 46624. List the emirps

Created by: ChrisR

2

40

#### Problem 50182. Compute the Euler totient function

Created by: ChrisR

1

9

#### Problem 60561. Determine whether a number is a Blum integer

Created by: ChrisR

0

6

#### Problem 50948. Identify prime words

Created by: ChrisR

Tags primes, strings

2

14

#### Problem 44098. Find my secret function I

Created by: Said BOUREZG

Tags primes

2

30

#### Problem 44099. Find my secret function II

Created by: Said BOUREZG

Tags primes

1

23

#### Problem 45367. Sieve of Eratosthenes - 02

Created by: Asif Newaz

2

18

#### Problem 46060. Identify primorial primes

Created by: ChrisR

1

14

#### Problem 54755. List odd twin composites

Created by: ChrisR

1

5

#### Problem 51720. Hoax Numbers

Created by: Dyuman Joshi

Tags primes, numbers

3

15

#### Problem 51798. Label primes with the Erdos-Selfridge classification

Created by: ChrisR

2

12

#### Problem 51312. Count the square-full divisors of a number

Created by: ChrisR

0

7

#### Problem 60581. List primes of the form xy+z

Created by: ChrisR

0

7

#### Problem 49733. Solve the arithmetic differential equation D(n) = n

Created by: ChrisR

0

10

#### Problem 46046. Determine whether a number is a cluster prime

Created by: ChrisR

4

17

#### Problem 46111. Evaluate the prime zeta function

Created by: ChrisR

1

15

#### Problem 52288. List Honaker primes

Created by: ChrisR

2

12

#### Problem 52639. Determine whether a number is unprimeable

Created by: ChrisR

3

14

#### Problem 47950. Test the generalized Legendre conjecture

Created by: ChrisR

0

13

#### Problem 896. Sophie Germain prime

Created by: Aurelien Queffurust

3

739

#### Problem 46047. Identify Wagstaff primes

Created by: ChrisR

Tags primes

2

29

#### Problem 46057. Find the last non-zero digit in a primorial

Created by: ChrisR

1

14

#### Problem 52956. Compute the largest number whose prime factors sum to n

Created by: ChrisR

1

8

#### Problem 55275. List the semiprimes

Created by: ChrisR

0

8

#### Problem 58018. List the Fermi-Dirac primes

Created by: ChrisR

2

8

Created by: HH

1

6

#### Problem 51198. Find pairs of primes with the same digit sum and a specified separation

Created by: ChrisR

1

12

Created by: goc3

7

436

#### Problem 47843. Compute the arithmetic derivative of integers

Created by: ChrisR

0

19

#### Problem 47793. Find the smallest prime with n inside

Created by: ChrisR

3

16

#### Problem 43087. Move if I am Optimus Prime

Created by: Jamil Kasan

Tags primes, jokes

8

36

#### Problem 2337. Sum of big primes without primes

Created by: Jean-Marie Sainthillier

3

127

#### Problem 56190. Split Even Number Into Two Primes

Created by: Ben Placek

Tags math, primes

6

191

#### Problem 52584. Easy Sequences 9: Faithful Pairs

Created by: Ramon Villamangca

1

16

#### Problem 45964. Compute the nth Pythagorean prime

Created by: ChrisR

1

29

1 – 50 of 101