A Comparison between angels and humans.  Angels…
  • never die (Luke 20:36)
  • are stronger, but not omnipotent/all powerful (Psalm 103:20; 2 Peter 2:11),
  • are greater than man in knowledge, but not omniscient/all knowing (2 Samuel 14:20; Matthew 24:36),
  • faithful angels are more noble and holy than man (Daniel 9:21-23, 10:10-14),
  • devoted angels can take on the appearance of men when God wills it. (Hebrews 13:2),
  • their appearance is at times described as dazzling white and blazing glory (Matthew 28:2-4),
  • have a will and can be tempted,
  • do not marry or reproduce (Matthew 22:30),
  • are not a race (Luke 20:34-36), and
  •  We are called “sons of men,” but angels are never called “sons of angels” because they cannot reproduce.  
Source: https://christiananswers.net/q-acb/acb-t005.html#wings / https://christiananswers.net/q-acb/acb-t005.html

Matthew 22:30-32 
At the resurrection people will neither marry nor be given in marriage; they will be like the angels in heaven. 31 But about the resurrection of the dead—have you not read what God said to you, 32 ‘I am the God of Abraham, the God of Isaac, and the God of Jacob’[a]? He is not the God of the dead but of the living.”

Who Are the Nephilim?

International Standard Bible Encyclopaedia
nef'-i-lim (nephilim): This word, translated "giants" in the King James Version, but retained in the Revised Version (British and American), is found in two passages of the Old Testament-one in Genesis 6:4, relating to the antediluvians; the other in Numbers 13:33, relating to the sons of Anak in Canaan.

In the former place the Nephilim are not necessarily to be identified with the children said to be borne "the daughters of men" to "the sons of God" (Genesis 6:2,4); indeed, they seem to be distinguished from the latter as upon the earth before this unholy commingling took place (see SONS OF GOD). But it is not easy to be certain as to the interpretation of this strange passage. In the second case they clearly represent men of gigantic stature, in comparison with whom the Israelites felt as if they were "grasshopers." This agrees with Genesis 6:4, "the mighty men that were of old, the men of renowned." Septuagint, therefore, was warranted in translating by gigantes. Written by James Orr

Easton's Bible DictionaryNephilim:
(Gen 6:4; Num 13:33, R.V.), giants, the Hebrew word left untranslated by the Revisers, the name of one of the Canaanitish tribes. The Revisers have, however, translated the Hebrew gibborim, in Gen 6:4, "mighty men."
​Resources ​Transliterated English
  • Strongs #  HebrewTransliteratedEnglish EquivalentOld Testament (Hebrew) for "angels"
    H47אַבִּיר'abbiyrbulls, strong (ones), mighty, stouthearted, valiant, angels, chiefest
    H430אֱלֹהִים'elohiymGod, god, judge, GOD, goddess, great, mighty, angels, exceeding, God-ward, godly
​Source: Blue Letter Bible

Publications
The Remnant Radio
On this episode of Donuts & Doctrine Josh Lewis and Jon Bunn discuss fallen angels, the Nephilim, and the book of Enoch. We discuss Dr. Michael Heisers "divine counsel theory", and other related theological topics such as angelology and demonology.