1605485809 has 2 divisors, whose sum is σ = 1605485810. Its totient is φ = 1605485808.

The previous prime is 1605485773. The next prime is 1605485821. The reversal of 1605485809 is 9085845061.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1151923600 + 453562209 = 33940^2 + 21297^2 .

It is a cyclic number.

It is not a de Polignac number, because 1605485809 - 2⁷ = 1605485681 is a prime.

It is not a weakly prime, because it can be changed into another prime (1605485879) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 802742904 + 802742905.

It is an arithmetic number, because the mean of its divisors is an integer number (802742905).

Almost surely, 2^1605485809 is an apocalyptic number.

It is an amenable number.

1605485809 is a deficient number, since it is larger than the sum of its proper divisors (1).

1605485809 is an equidigital number, since it uses as much as digits as its factorization.

1605485809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 345600, while the sum is 46.

The square root of 1605485809 is about 40068.5139355080. The cubic root of 1605485809 is about 1170.9422873877.

The spelling of 1605485809 in words is "one billion, six hundred five million, four hundred eighty-five thousand, eight hundred nine".