1604394778289 has 4 divisors (see below), whose sum is σ = 1604444902260. Its totient is φ = 1604344654320.

The previous prime is 1604394778229. The next prime is 1604394778313. The reversal of 1604394778289 is 9828774934061.

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 25268281600 + 1579126496689 = 158960^2 + 1256633^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1604394778289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1604394778229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25013942 + ... + 25077999.

It is an arithmetic number, because the mean of its divisors is an integer number (401111225565).

Almost surely, 2^{1604394778289} is an apocalyptic number.

It is an amenable number.

1604394778289 is a deficient number, since it is larger than the sum of its proper divisors (50123971).

1604394778289 is an equidigital number, since it uses as much as digits as its factorization.

1604394778289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50123970.

The product of its (nonzero) digits is 146313216, while the sum is 68.

The spelling of 1604394778289 in words is "one trillion, six hundred four billion, three hundred ninety-four million, seven hundred seventy-eight thousand, two hundred eighty-nine".