Useful mathematical/scientific characters

Name Symbol Encoding
Degrees
°
°
Prime
′
Double prime
″
Square root
√
Cube root
∛
Plus or minus
±
±
Product
×
×
Dot operator
⋅
Circle operator
∘
Direct sum
⊕
Congruent to
≡
Not congruent to
≢
Asymptotic to
∼
Approximately equal
≈
Less than approx.
≲
Greater than approx.
≳
Isomorphic to
≅
Proportional to
∝
Much greater than
≫
Much less than
≪
Member of
∈
Not member of
∉
Intersection
∩
Union
∪
Contained in
⊆
Not contained in
⊈
Strictly contained in
⊂
Contains
⊇
Doesn't contain
⊉
Strictly contains
⊃
Repeated sum
∑
Repeated product
∏
Integral
∫
Gradient
∇
Divides
∣
Doesn't divide
∤
Double vertical bars
∥
Maps to
→
Element maps to
↦
Bidirectional arrows
⇄
If and only if
⇔
Infinity
∞
Planck's constant
ℎ
Planck's constant / 2π
ℏ
Circled dot
⊙
Weierstrass P
℘
Cyrillic Sha (capital)
Ш
Ш
Complex numbers
ℂ
Quaternions
ℍ
Natural numbers
ℕ
Projective space
ℙ
Rational numbers
ℚ
Real numbers
ℝ
Integers
ℤ