20818109 has 8 divisors (see below), whose sum is σ = 22585080. Its totient is φ = 19074816.

The previous prime is 20818099. The next prime is 20818121. The reversal of 20818109 is 90181802.

It can be written as a sum of positive squares in 4 ways, for example, as 6400900 + 14417209 = 2530^2 + 3797^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20818109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20818139) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4064 + ... + 7625.

It is an arithmetic number, because the mean of its divisors is an integer number (2823135).

Almost surely, 2^20818109 is an apocalyptic number.

It is an amenable number.

20818109 is a deficient number, since it is larger than the sum of its proper divisors (1766971).

20818109 is a wasteful number, since it uses less digits than its factorization.

20818109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11839.

The product of its (nonzero) digits is 1152, while the sum is 29.

The square root of 20818109 is about 4562.6865989239. The cubic root of 20818109 is about 275.0935615529.

The spelling of 20818109 in words is "twenty million, eight hundred eighteen thousand, one hundred nine".