16728537509 has 4 divisors (see below), whose sum is σ = 17305383660. Its totient is φ = 16151691360.

The previous prime is 16728537503. The next prime is 16728537521. The reversal of 16728537509 is 90573582761.

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 4502812609 + 12225724900 = 67103^2 + 110570^2 .

It is a cyclic number.

It is not a de Polignac number, because 16728537509 - 2³² = 12433570213 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 (16728537503) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 288423032 + ... + 288423089.

It is an arithmetic number, because the mean of its divisors is an integer number (4326345915).

Almost surely, 2^16728537509 is an apocalyptic number.

It is an amenable number.

16728537509 is a deficient number, since it is larger than the sum of its proper divisors (576846151).

16728537509 is an equidigital number, since it uses as much as digits as its factorization.

16728537509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 576846150.

The product of its (nonzero) digits is 3175200, while the sum is 53.

The spelling of 16728537509 in words is "sixteen billion, seven hundred twenty-eight million, five hundred thirty-seven thousand, five hundred nine".