I talked about this a little bit in Has an inverted cross ever meant Satanism?, but popular depictions of "Satanic" imagery tend to accrete over time. Some of them have ultimate sources from Biblical or quasi-Biblical traditions, others are borrowed from other esoteric sources or even popular poems. For the elements you're talking about:

evil numbers (666)

And that no man might buy or sell, save he that had the mark, or the name of the beast, or the number of his name. 18Here is wisdom. Let him that hath understanding count the number of the beast: for it is the number of a man; and his number is six hundred and sixty-six.

• Revelation 13:15–18

The "Number of the Beast" is actually in the Bible, although there is an alternate reading of it being 616. These are both part of a practice of numerology called gematria where letters are encoded as numbers (e.g. a = 1, b = 2, etc.) which is part of some esoteric traditions such as medieval Jewish Quabbalah. There have been many different interpretations as to who the authors had in mind when they chose 616 as a number (Nero being a popular candidate for his persecution of early Christians), but in Satanic terms, the idea was strongly popularized by Aleister Crowley, who described himself as "the Beast 666," and through the association it filtered into popular culture through films like The Omen (1976) and the Norwegian black metal band 666 ("sax-sax-sax" 1982).

demon summoning pentagrams

Not in the Bible, put a popular component of the Western grimoire tradition. The association was not always explicitly with demons, but spirits and magical operations of many types often involved drawing geometric figures, circles, seals, etc. for purposes of conjuration from late antiquity through the Renaissance. Éliphas Lévi emphasized the importance of the pentragram as a symbol and in magical operations in books like Histoire de la magie (1860), and Aleister Crowley drew the distinction between the upright pentagram as a symbol of protection and the inverted (point down) pentagram as a symbol of evil or conjuration. Anton LaVey would draw on this when creating the symbol for the Church of Satan which he founded in 1966, which is an inverted pentagram containing a goat's face ("the Sigil of Baphomet"); LaVey had modified/borrowed it from Maurice Bessy's A Pictorial History of Magic and the Supernatural (1964), and Bessy in turn took it from La Clef de la Magie Noire (1897) by Stanislas De Guaita, who was in turn influenced by Lévi.

goat horned devils

This one's a bit more complicated, and there's been a lot of speculation on the subject. Ancient and medieval depictions of demons and devils, much less "the" Devil or Satan, tend to be complex and varied; there has never been any single consistent image of the Devil - readers of the Bible have drawn on allusions to goats, pigs, snakes, and other creatures for inspiration in creating demons, and the descriptions in Goetic grimoires with their lists of spirits tend to get creative.

Lévi in his book Dogme et Rituel de la Haute Magie (1856) interpreted some of the this material in creating the striking illustration of the figure of Sabbatic goat (i.e. the goat of the Witches' Sabbat, which would receive the osculum infame - the kiss of shame, where a witch was initiated by kissing the hindquarters) - but Lévi interpreted this as a symbolic figure, not a literal representation of the devil; he also drew a line of association with the Goat of Mendes, a figure of worship mentioned in Herodotus.

Regardless of his intentions, the goat-headed figure of Lévi's helped popularize both the image of the goat-headed devil and its association with the name Baphomet, a term referring to one of the heresies claimed against the Knights Templar during their trial and subsequent destruction. The most popular tarot deck, the Rider-Waite Tarot, uses a goat-horned and hairy Devil with a pentagram on his forehead for one of the trumps because of Lévi's influence, and Léo Taxil adopted the Sabbatic Goat image for his anti-Masonic hoax Les Mystères de la franc-maçonnerie dévoilés (1886). Crowley and later Anton LaVey both adopted Baphomet and the goat-image, and helped spread their association.

Which is not to say that all images of goat-headed devils come from Lévi, Crowley, and LaVey! As I said, it's complicated and there were a lot of different influences that went into the popular conception of the Devil as goat-headed, which has influenced everything from Francisco Goya's paintings El aquelarre (1798) and Aquelarre or El gran cabrón (1823) to Black Phillip in The VVitch (2015) to H. P. Lovecraft's Shub-Niggurath, The Black Goat of the Woods with a Thousand Young. But a great deal of the contemporary imagery of the goat as Satanic in popular culture owes much to the popularization of that particular image by Lévi, Crowley, and LaVey. When Jack Chick is making a goat-headed devil for his Chick Tracts, he generally didn't dive into some medieval artwork for a goat-headed figure.

I have deliberately avoided mentioning the ancient Greco-Roman figure of Pan, who is often depicted as a satyresque or faun-like figure. Arguments that Pan was the (or at least a) inspiration for the popular satyr-like Devil have been around for a while, but there isn't strong evidence of it, and much of the argument dates back to the turn of the century and after when Pan underwent a brief revival in art and literature (not all of it negative, the figure of Peter Pan is at least partially inspired by the idea of Pan as a figure of freedom). Margaret Murray in particular argued the point in The God of the Witches (1933), which influenced subsequent neopagan, Wiccan, and LaVeyan Satanism movements. So while the medieval devil probably wasn't directly inspired by Pan, there are definitely some contemporary versions which are.