Get Math Help

GET TUTORING NEAR ME!

By submitting the following form, you agree to Club Z!'s Terms of Use and Privacy Policy

    Solitary Number

    Definition

    A solitary number is a number which does not have any friends. Solitary numbers include all primes, prime powers, and numbers for which (n, σ(n)) = 1, where (a, b) is the greatest common divisor of a and b and σ(n) is the divisor function. The first few numbers satisfying (n, σ(n)) = 1 are 1, 2, 3, 4, 5, 7, 8, 9, 11, 13, 16, 17, 19, 21, ... (OEIS A014567). Numbers such as 18, 45, 48, 52, 136, 148, 160, 162, 176, 192, 196, 208, 232, 244, 261, 272, 292, 296, 297, 304, 320, 352, and 369 can also be easily proved to be solitary.

    Find the right fit or it’s free.

    We guarantee you’ll find the right tutor, or we’ll cover the first hour of your lesson.