19647845813 has 16 divisors (see below), whose sum is σ = 20145250800. Its totient is φ = 19156646400.

The previous prime is 19647845801. The next prime is 19647845837. The reversal of 19647845813 is 31854874691.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 8086865329 + 11560980484 = 89927^2 + 107522^2 .

It is a cyclic number.

It is not a de Polignac number, because 19647845813 - 2⁴ = 19647845797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19647845513) 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 in 15 ways as a sum of consecutive naturals, for example, 5060633 + ... + 5064513.

It is an arithmetic number, because the mean of its divisors is an integer number (1259078175).

Almost surely, 2^19647845813 is an apocalyptic number.

It is an amenable number.

19647845813 is a deficient number, since it is larger than the sum of its proper divisors (497404987).

19647845813 is a wasteful number, since it uses less digits than its factorization.

19647845813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4648.

The product of its digits is 5806080, while the sum is 56.

The spelling of 19647845813 in words is "nineteen billion, six hundred forty-seven million, eight hundred forty-five thousand, eight hundred thirteen".