1604561689 has 2 divisors, whose sum is σ = 1604561690. Its totient is φ = 1604561688.

The previous prime is 1604561669. The next prime is 1604561729. The reversal of 1604561689 is 9861654061.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1411129225 + 193432464 = 37565^2 + 13908^2 .

It is a cyclic number.

It is not a de Polignac number, because 1604561689 - 2⁹ = 1604561177 is a prime.

It is not a weakly prime, because it can be changed into another prime (1604561639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 802280844 + 802280845.

It is an arithmetic number, because the mean of its divisors is an integer number (802280845).

Almost surely, 2^1604561689 is an apocalyptic number.

It is an amenable number.

1604561689 is a deficient number, since it is larger than the sum of its proper divisors (1).

1604561689 is an equidigital number, since it uses as much as digits as its factorization.

1604561689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 311040, while the sum is 46.

The square root of 1604561689 is about 40056.9805277432. The cubic root of 1604561689 is about 1170.7175788987.

The spelling of 1604561689 in words is "one billion, six hundred four million, five hundred sixty-one thousand, six hundred eighty-nine".