40685809 has 2 divisors, whose sum is σ = 40685810. Its totient is φ = 40685808.

The previous prime is 40685797. The next prime is 40685831. The reversal of 40685809 is 90858604.

40685809 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 24039409 + 16646400 = 4903^2 + 4080^2 .

It is a cyclic number.

It is not a de Polignac number, because 40685809 - 2⁹ = 40685297 is a prime.

It is not a weakly prime, because it can be changed into another prime (40685839) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20342904 + 20342905.

It is an arithmetic number, because the mean of its divisors is an integer number (20342905).

Almost surely, 2^40685809 is an apocalyptic number.

It is an amenable number.

40685809 is a deficient number, since it is larger than the sum of its proper divisors (1).

40685809 is an equidigital number, since it uses as much as digits as its factorization.

40685809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 69120, while the sum is 40.

The square root of 40685809 is about 6378.5428586786. The cubic root of 40685809 is about 343.9386524142.

The spelling of 40685809 in words is "forty million, six hundred eighty-five thousand, eight hundred nine".