Bsrgvty

It was stated in one of the books of Agniveer that Shatapatha Brahmana states that Vedas have 8.64 lakh alphabets.

Can anyone quote the actual text from Shatapatha Bahmana, wherein it was stated so?

It's in the AgniRahasya kanda of Shatapatha Brahmana:

स ऋचो व्यौहत् । द्वादश बृहतीसहस्राण्येतावत्यो हर्चो याः प्रजापतिसृष्टास्तास्त्रिंशत्तमे व्यूहे पङ्क्तिष्वतिष्ठन्त ता यत्त्रिंशत्तमे व्यूहेऽतिष्ठन्त तस्मात्त्रिंशन्मासस्य रात्रयोऽथ यत्पङ्क्तिषु तस्मात्पाङ्क्तः प्रजापतिस्ता अष्टाशतं शतानि पङ्क्तयोऽभवन् - १०.४.२.[२३]


अथेतरौ वेदौ व्यौहत्। द्वादशैव बृहतीसहस्राण्यष्टौ यजुषां चत्वारि साम्नामेतावद्धैतयोर्वेदयोर्यत्प्रजापतिसृष्टं तौ त्रिंशत्तमे व्यूहे पङ्क्तिष्वतिष्ठेतां तौ यत्त्रिंशत्तमे व्यूहेऽतिष्ठेतां तस्मात्त्रिंशन्मासस्य रात्रयोऽथ यत्पङ्क्तिषु तस्मात्पाङ्क्तः प्रजापतिस्ता अष्टाशतमेव शतानि पङ्क्तयोऽभवन् - १०.४.२.[२४]


He arranged the Rik-verses into twelve thousand of Brihatis, for of that extent are the verses created by Prajapati. At-the thirtieth arrangement they came to an end in the Paṅktis; and because it was at the thirtieth arrangement that they came to an end, there are thirty Ratris in the Masa; and because it was in the Paṅktis, therefore Prajapati is 'Pankta' (fivefold). There are one hundred-and-eight hundred Panktis. He then arranged the two other Vedas into twelve thousand Brihatis,--eight (thousand) of the Yajus, and four of the Saman-- for of that extent is what was created by Prajapati in these two Vedas. At the thirtieth arrangement these two came to an end in the Panktis; and because it was at the thirtieth arrangement that they came to an end, there are thirty Ratris in the Masa; and because it was in the Paṅktis, therefore Prajapati is 'pankta' There were one hundred-and-eight hundred Paṅktis. [Shatapatha Brahamana 10.4.2]

As mentioned above there Riks can be arranged as 108 hundred Panktis and Saman + Yajus can be arranged as 108 hundred Panktis.



Rik + Yaju + Saman - complete of all Vedas



Each Pankti verse consist of 40 syllables;

40*10800 +40*10800

=432000 +432000

=864000

Thus, there are 864000 Aksharas in Vedas. But there is also concept of Daivi Pankti chhandas and other type of Pankti chhandas where 1 or 2 letters can be more or less in a Pankti chhanda. So, it's possible that this number could vary in certain circumstances. But generally it can be considered that 1 pankti = 40 Aksharas.