Sphenic number

In number theory, a sphenic number (from Ancient Greek: σφήνα, 'wedge') is a positive integer that is the product of three distinct prime numbers. In number theory, a sphenic number (from Ancient Greek: σφήνα, 'wedge') is a positive integer that is the product of three distinct prime numbers. A sphenic number is a product pqr where p, q, and r are three distinct prime numbers.This definition is more stringent than simply requiring the integer to have exactly three prime factors. For instance, 60 = 22 × 3 × 5 has exactly 3 prime factors, but is not sphenic. The sphenic numbers are the square-free 3-almost primes.