Let ABCDEFG represent the 7-digit odd number: G is odd, so G=1, 3, 5, 7 or 9.
3 stands for 3 tens: F=3.
The product of the digit in the millions place and the digit in the tens place is 15:
The value of the 9 digit is 90000: C=9.
Sum of all digits=30: A+B+C+D+E+F+G=30=5+B+9+D+E+3+G, B+D+E+G=30-17=13.
The digit 8 is in the thousands place: D=8.
This digit is twice the digit in the 100s place: 8=2E, E=8/2=4. D+E=12, B+G=13-12=1.
The difference between the digit in the millions place and ones place is 4: A-G=4, G=5-4=1.
The number is 5098431.