A single vertical friction pile of diameter 500 mm and length 20 m is subjected to a vertical compressive load. The pile is embedded in a homogeneous sandy stratum where: angle of internal friction (φ) = 30°, dry unit weight (γ_d) = 20 kN/m³, angle of wall friction (δ) = 2φ/3, and coefficient of lateral earth pressure (K) = 2.7. Considering the bearing capacity factor (N_q) = 25, the ultimate bearing capacity of the pile (in kN) is ______.