20680009 has 6 divisors (see below), whose sum is σ = 24056394. Its totient is φ = 17725680.

The previous prime is 20680001. The next prime is 20680021. The reversal of 20680009 is 90008602.

It can be written as a sum of positive squares in only one way, i.e., 12996025 + 7683984 = 3605^2 + 2772^2 .

It is not a de Polignac number, because 20680009 - 2³ = 20680001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20680001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 210972 + ... + 211069.

It is an arithmetic number, because the mean of its divisors is an integer number (4009399).

Almost surely, 2^20680009 is an apocalyptic number.

It is an amenable number.

20680009 is a deficient number, since it is larger than the sum of its proper divisors (3376385).

20680009 is an equidigital number, since it uses as much as digits as its factorization.

20680009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 422055 (or 422048 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 20680009 is about 4547.5277899096. The cubic root of 20680009 is about 274.4839202572.

The spelling of 20680009 in words is "twenty million, six hundred eighty thousand, nine".