natural number denoted by the symbol  is - 

List of Mathematical Symbols • R = real numbers, Z = integers, N=natural numbers, Q = rational numbers, P = irrational numbers. • ⊂= proper subset (not the whole thing) ⊆=subset • ∃ = there exists • ∀ = for every • ∈= element of • S = union (or) • T = intersection (and) • s.t.= such that • =⇒ implies • ⇐⇒ if and only if • P = sum • = set minus • ∴= therefore