Shiva Purana
चतुर्विंशतिलक्षं वा गायत्र्या जपसंयुतः । ब्राह्मणस्तु भवेत्पात्रं संपूर्णफलभोगदम् १४ ।
A brahmin who has repeated the Gāyatrī mantra two million four hundred thousand times also deserves the same and accords full benefit and wordly enjoyments.
english translation
caturviMzatilakSaM vA gAyatryA japasaMyutaH । brAhmaNastu bhavetpAtraM saMpUrNaphalabhogadam 14 ।
hk transliteration by Sanscript