Prime factors of 450 is 2×3×3×5×5. Now, non-prime divisors will be combinations of these. When two are multiplied, 2×3=6,2×5=10 3×3=9,3×5=15,5×5=25 When three are multiplied, ‌2×3×3=18,2×3×5=30,2×5×5×=50, ‌3×3×5=45,3×5×5=75 When four are multiplied, ‌2×3×3×5=90,2×3×5×5=150, ‌3×3×5×5=225 When five are multiplied, 2×3×3×5×5=450 Also, 1 is also a non-prime divisor. So, sum of divisors =9+15+25+30+50+45+75+90 +150+225+450+1=1199