1604663521 has 2 divisors, whose sum is σ = 1604663522. Its totient is φ = 1604663520.

The previous prime is 1604663513. The next prime is 1604663569. The reversal of 1604663521 is 1253664061.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1602881296 + 1782225 = 40036^2 + 1335^2 .

It is a cyclic number.

It is not a de Polignac number, because 1604663521 - 2³ = 1604663513 is a prime.

It is not a weakly prime, because it can be changed into another prime (1604663321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 802331760 + 802331761.

It is an arithmetic number, because the mean of its divisors is an integer number (802331761).

Almost surely, 2^1604663521 is an apocalyptic number.

It is an amenable number.

1604663521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1604663521 is an equidigital number, since it uses as much as digits as its factorization.

1604663521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 34.

The square root of 1604663521 is about 40058.2515968932. The cubic root of 1604663521 is about 1170.7423445385.

The spelling of 1604663521 in words is "one billion, six hundred four million, six hundred sixty-three thousand, five hundred twenty-one".