Use the compound interest formula.
Let A = the ending amount
Let P = the principal
Let r = the interest rate
Let n = the amount compounded a year
Let t = time
A = P(1 + r/n) ^(n/t)
Substitute your numbers in
1,000,000 = P(1 + .07/365)^(365/30). Divide each side by (1 + .07/365)^(365/30).
365 / 30 = 10,950
1,000,000/(1 + .07/365)^(10,950) = P. Calculate your value for P.
$122,481.09 = P