40 has 8 factors in total.

Quick answer

The positive factors of 40 are:

  • 1, 2, 4, 5, 8, 10, 20, 40.

So the number of factors of 40 is 8.

How to see this quickly

Think of the prime factorization:

  • 40=23×5140=2^3\times 5^140=23×51.

To count the number of positive factors, use:

  • If n=p1a×p2bn=p_1^{a}\times p_2^{b}n=p1a​×p2b​, then number of factors =(a+1)(b+1)=(a+1)(b+1)=(a+1)(b+1).
  • Here (3+1)(1+1)=4×2=8(3+1)(1+1)=4\times 2=8(3+1)(1+1)=4×2=8.

So 40 has 8 positive divisors, which match the list above.

Information gathered from public forums or data available on the internet and portrayed here.