20906818209 has 12 divisors (see below), whose sum is σ = 30710581200. Its totient is φ = 13701643224.

The previous prime is 20906818199. The next prime is 20906818211. The reversal of 20906818209 is 90281860902.

It is not a de Polignac number, because 20906818209 - 2¹⁶ = 20906752673 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20906818109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19685739 + ... + 19686800.

It is an arithmetic number, because the mean of its divisors is an integer number (2559215100).

Almost surely, 2^20906818209 is an apocalyptic number.

It is an amenable number.

20906818209 is a deficient number, since it is larger than the sum of its proper divisors (9803762991).

20906818209 is a wasteful number, since it uses less digits than its factorization.

20906818209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39372604 (or 39372601 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 45.

The spelling of 20906818209 in words is "twenty billion, nine hundred six million, eight hundred eighteen thousand, two hundred nine".