3991585322645 has 4 divisors (see below), whose sum is σ = 4789902387180. Its totient is φ = 3193268258112.

The previous prime is 3991585322639. The next prime is 3991585322663. The reversal of 3991585322645 is 5462235851993.

3991585322645 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 991231307236 + 3000354015409 = 995606^2 + 1732153^2 .

It is a cyclic number.

It is not a de Polignac number, because 3991585322645 - 2¹⁰ = 3991585321621 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 399158532260 + ... + 399158532269.

It is an arithmetic number, because the mean of its divisors is an integer number (1197475596795).

Almost surely, 2^{3991585322645} is an apocalyptic number.

It is an amenable number.

3991585322645 is a deficient number, since it is larger than the sum of its proper divisors (798317064535).

3991585322645 is an equidigital number, since it uses as much as digits as its factorization.

3991585322645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 798317064534.

The product of its digits is 69984000, while the sum is 62.

The spelling of 3991585322645 in words is "three trillion, nine hundred ninety-one billion, five hundred eighty-five million, three hundred twenty-two thousand, six hundred forty-five".