16565939897 has 6 divisors (see below), whose sum is σ = 17938266462. Its totient is φ = 15291636672.

The previous prime is 16565939881. The next prime is 16565939917. The reversal of 16565939897 is 79893956561.

It can be written as a sum of positive squares in 3 ways, for example, as 194993296 + 16370946601 = 13964^2 + 127949^2 .

It is not a de Polignac number, because 16565939897 - 2⁴ = 16565939881 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16565939827) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 49011488 + ... + 49011825.

It is an arithmetic number, because the mean of its divisors is an integer number (2989711077).

Almost surely, 2^16565939897 is an apocalyptic number.

It is an amenable number.

16565939897 is a deficient number, since it is larger than the sum of its proper divisors (1372326565).

16565939897 is an equidigital number, since it uses as much as digits as its factorization.

16565939897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98023339 (or 98023326 counting only the distinct ones).

The product of its digits is 110224800, while the sum is 68.

The spelling of 16565939897 in words is "sixteen billion, five hundred sixty-five million, nine hundred thirty-nine thousand, eight hundred ninety-seven".