Friction between feelings and pride. This sum stirs touchy relationships and stop-start projects; choose words carefully and let small slights pass to keep your momentum.
Sum 21 belongs to the group traditional readers advise avoiding, as it is believed to invite friction and fatigue. If you must use it, choose a number whose internal pairs are strong enough to compensate.
Add all 10 digits of the number, e.g. 099-296-9696 = 0+9+9+2+9+6+9+6+9+6 = 65, then read the total against the numerology table — this page covers sum 21.