1604428561 has 4 divisors (see below), whose sum is σ = 1634700852. Its totient is φ = 1574156272.

The previous prime is 1604428537. The next prime is 1604428621. The reversal of 1604428561 is 1658244061.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1466507025 + 137921536 = 38295^2 + 11744^2 .

It is a cyclic number.

It is not a de Polignac number, because 1604428561 - 2⁷ = 1604428433 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1604428561.

It is not an unprimeable number, because it can be changed into a prime (1604458561) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15136066 + ... + 15136171.

It is an arithmetic number, because the mean of its divisors is an integer number (408675213).

Almost surely, 2^1604428561 is an apocalyptic number.

It is an amenable number.

1604428561 is a deficient number, since it is larger than the sum of its proper divisors (30272291).

1604428561 is an equidigital number, since it uses as much as digits as its factorization.

1604428561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30272290.

The product of its (nonzero) digits is 46080, while the sum is 37.

The square root of 1604428561 is about 40055.3187604343. The cubic root of 1604428561 is about 1170.6852004613.

The spelling of 1604428561 in words is "one billion, six hundred four million, four hundred twenty-eight thousand, five hundred sixty-one".