Decrees that affect health tanking and survivability:

• Greedy Heal: Killing enemies restores 10/20/30/40/50% Health.
• Corrosive Grit: Each stack of Corrosive grants 60/120/180 Armor, up to 5x, for 12 seconds.
• Tamm's Fortune: Finisher attacks grant +500 Armor for 10 seconds. Armor boost triples for Warframe.
• Rain of Vitality: Enemies have +60% additional chance to drop Health Orb. Health Orbs increase Armor by 80/160/240 for 10 seconds. Effect triples for Warframe.
• Marauder's Nerve: Reduce incoming damage by 3% per Decree up to 75%.
• Fortified Will: Every 50 Armor grants 5%/10%/15% Ability Strength and Power Strike damage. (Capped at 500% Ability Strength - feeds back into elemental ward)

EHP CALCULATIONS
Total health: Blessing (1200) + 444 (base) + 444 ([Archon Vitality]) = 2088
Total armor: 444 (base) + 1350 ([Health Conversion]) + 2644 ([Mecha Pulse] on 10 enemies = 444x60%x10) + 900 (corrosive crit) + 1500 (Tamm's fortune) + 720 (Rain of Vitality) + Fortified Will boosted Cold Elemental Ward (444x1.45x6 = 3862) = 11420 armor
Damage reduction from armor: 11420/(11420+300) = 97.44%
Total damage reduction: 90% (adaptation) x 97.44 (armor) x 75% (Maurander's Nerve) x 75% (arcane double back) x 40% (aviator) = 1 - (1-0.9) x (1-0.9744) x(1-0.75) x (1-0.75) = 0.99990401023 or 99.99% damage reduction (in maximum conditions).

MAXIMUM EHP WHILE JUMPING AND ALL RELEVANT ABILITIES/DECREES/CONDITIONS ACTIVE
2088 / (1-0.99990401023) = 21,752,320 ehp

For comparison, [Inaros] with Triumbral [Adaptation] + [Aviator] + double back + eclipse all active has about the same ehp.