169505909 has 2 divisors, whose sum is σ = 169505910. Its totient is φ = 169505908.

The previous prime is 169505891. The next prime is 169505911. The reversal of 169505909 is 909505961.

169505909 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 103083409 + 66422500 = 10153^2 + 8150^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-169505909 is a prime.

Together with 169505911, it forms a pair of twin primes.

It is a Chen prime.

It is a nialpdrome in base 11.

It is a self number, because there is not a number n which added to its sum of digits gives 169505909.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (169505969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84752954 + 84752955.

It is an arithmetic number, because the mean of its divisors is an integer number (84752955).

Almost surely, 2^169505909 is an apocalyptic number.

It is an amenable number.

169505909 is a deficient number, since it is larger than the sum of its proper divisors (1).

169505909 is an equidigital number, since it uses as much as digits as its factorization.

169505909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 109350, while the sum is 44.

The square root of 169505909 is about 13019.4434980916. The cubic root of 169505909 is about 553.4286195398.

The spelling of 169505909 in words is "one hundred sixty-nine million, five hundred five thousand, nine hundred nine".