15997385809 has 4 divisors (see below), whose sum is σ = 15998606500. Its totient is φ = 15996165120.

The previous prime is 15997385777. The next prime is 15997385827. The reversal of 15997385809 is 90858379951.

15997385809 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, and also an emirpimes, since its reverse is a distinct semiprime: 90858379951 = 577 ⋅157466863.

It can be written as a sum of positive squares in 2 ways, for example, as 6388485184 + 9608900625 = 79928^2 + 98025^2 .

It is a cyclic number.

It is not a de Polignac number, because 15997385809 - 2⁵ = 15997385777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15997385839) 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 3 ways as a sum of consecutive naturals, for example, 590472 + ... + 616969.

It is an arithmetic number, because the mean of its divisors is an integer number (3999651625).

Almost surely, 2^15997385809 is an apocalyptic number.

It is an amenable number.

15997385809 is a deficient number, since it is larger than the sum of its proper divisors (1220691).

15997385809 is a wasteful number, since it uses less digits than its factorization.

15997385809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1220690.

The product of its (nonzero) digits is 24494400, while the sum is 64.

The spelling of 15997385809 in words is "fifteen billion, nine hundred ninety-seven million, three hundred eighty-five thousand, eight hundred nine".