169728809 has 2 divisors, whose sum is σ = 169728810. Its totient is φ = 169728808.

The previous prime is 169728791. The next prime is 169728817. The reversal of 169728809 is 908827961.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 169728784 + 25 = 13028^2 + 5^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-169728809 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (169728409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84864404 + 84864405.

It is an arithmetic number, because the mean of its divisors is an integer number (84864405).

Almost surely, 2^169728809 is an apocalyptic number.

It is an amenable number.

169728809 is a deficient number, since it is larger than the sum of its proper divisors (1).

169728809 is an equidigital number, since it uses as much as digits as its factorization.

169728809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 435456, while the sum is 50.

The square root of 169728809 is about 13028.0009594719. Note that the first 3 decimals coincide. The cubic root of 169728809 is about 553.6710992014.

The spelling of 169728809 in words is "one hundred sixty-nine million, seven hundred twenty-eight thousand, eight hundred nine".