20008909 has 2 divisors, whose sum is σ = 20008910. Its totient is φ = 20008908.

The previous prime is 20008907. The next prime is 20008913. The reversal of 20008909 is 90980002.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18576100 + 1432809 = 4310^2 + 1197^2 .

It is a cyclic number.

It is not a de Polignac number, because 20008909 - 2¹ = 20008907 is a prime.

Together with 20008907, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20008903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10004454 + 10004455.

It is an arithmetic number, because the mean of its divisors is an integer number (10004455).

Almost surely, 2^20008909 is an apocalyptic number.

It is an amenable number.

20008909 is a deficient number, since it is larger than the sum of its proper divisors (1).

20008909 is an equidigital number, since it uses as much as digits as its factorization.

20008909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 20008909 is about 4473.1319005815. The cubic root of 20008909 is about 271.4820602540.

The spelling of 20008909 in words is "twenty million, eight thousand, nine hundred nine".