16565028509 has 2 divisors, whose sum is σ = 16565028510. Its totient is φ = 16565028508.

The previous prime is 16565028461. The next prime is 16565028511. The reversal of 16565028509 is 90582056561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10601791225 + 5963237284 = 102965^2 + 77222^2 .

It is a cyclic number.

It is not a de Polignac number, because 16565028509 - 2²⁰ = 16563979933 is a prime.

Together with 16565028511, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16565028409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8282514254 + 8282514255.

It is an arithmetic number, because the mean of its divisors is an integer number (8282514255).

Almost surely, 2^16565028509 is an apocalyptic number.

It is an amenable number.

16565028509 is a deficient number, since it is larger than the sum of its proper divisors (1).

16565028509 is an equidigital number, since it uses as much as digits as its factorization.

16565028509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648000, while the sum is 47.

The spelling of 16565028509 in words is "sixteen billion, five hundred sixty-five million, twenty-eight thousand, five hundred nine".