16688909 has 2 divisors, whose sum is σ = 16688910. Its totient is φ = 16688908.

The previous prime is 16688899. The next prime is 16688911. The reversal of 16688909 is 90988661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9517225 + 7171684 = 3085^2 + 2678^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16688909 is a prime.

It is a super-2 number, since 2×16688909² = 557039367220562, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 16688911, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16688939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8344454 + 8344455.

It is an arithmetic number, because the mean of its divisors is an integer number (8344455).

Almost surely, 2^16688909 is an apocalyptic number.

It is an amenable number.

16688909 is a deficient number, since it is larger than the sum of its proper divisors (1).

16688909 is an equidigital number, since it uses as much as digits as its factorization.

16688909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 186624, while the sum is 47.

The square root of 16688909 is about 4085.2061147511. The cubic root of 16688909 is about 255.5500570196.

The spelling of 16688909 in words is "sixteen million, six hundred eighty-eight thousand, nine hundred nine".