Representation numerals

μ

٤٠

XL

●●

ↂ

四十

מ

Numeral systems

Binary: 101000

Septimal (base 7): 55

Octal: 50

Hexadecimal: 28

Base 24: 1G

Factorization

40 = 2 × 2 × 2 × 5

40 has 8 divisors: 1, 2, 4, 5, 8, 10, 20, 40

Sum of all divisors other than 40: 50

Sums & differences

Sum of 2 squares: 40 = 6^{2} + 2^{2}

Difference of 2 squares: 40 = 7^{2} - 3^{2} = 11^{2} - 9^{2}

Goldbach conjecture: 40 = 37 + 3 = 29 + 11 = 23 + 17

Characteristics

40 is a octogonal number

40 is a palindromic number in septimal system (55)