40785809 has 2 divisors, whose sum is σ = 40785810. Its totient is φ = 40785808.

The previous prime is 40785793. The next prime is 40785817. The reversal of 40785809 is 90858704.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 32171584 + 8614225 = 5672^2 + 2935^2 .

It is a cyclic number.

It is not a de Polignac number, because 40785809 - 2⁴ = 40785793 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (40785709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20392904 + 20392905.

It is an arithmetic number, because the mean of its divisors is an integer number (20392905).

Almost surely, 2^40785809 is an apocalyptic number.

It is an amenable number.

40785809 is a deficient number, since it is larger than the sum of its proper divisors (1).

40785809 is an equidigital number, since it uses as much as digits as its factorization.

40785809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 80640, while the sum is 41.

The square root of 40785809 is about 6386.3768288443. The cubic root of 40785809 is about 344.2202061555.

The spelling of 40785809 in words is "forty million, seven hundred eighty-five thousand, eight hundred nine".