40085809 has 2 divisors, whose sum is σ = 40085810. Its totient is φ = 40085808.

The previous prime is 40085807. The next prime is 40085827. The reversal of 40085809 is 90858004.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 24285184 + 15800625 = 4928^2 + 3975^2 .

It is a cyclic number.

It is not a de Polignac number, because 40085809 - 2¹ = 40085807 is a prime.

Together with 40085807, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (40085807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20042904 + 20042905.

It is an arithmetic number, because the mean of its divisors is an integer number (20042905).

Almost surely, 2^40085809 is an apocalyptic number.

It is an amenable number.

40085809 is a deficient number, since it is larger than the sum of its proper divisors (1).

40085809 is an equidigital number, since it uses as much as digits as its factorization.

40085809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11520, while the sum is 34.

The square root of 40085809 is about 6331.3354831347. The cubic root of 40085809 is about 342.2395668803.

The spelling of 40085809 in words is "forty million, eighty-five thousand, eight hundred nine".