20985109 has 8 divisors (see below), whose sum is σ = 21800192. Its totient is φ = 20178720.

The previous prime is 20985059. The next prime is 20985113. The reversal of 20985109 is 90158902.

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-20985109 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20985119) 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, 2977 + ... + 7129.

It is an arithmetic number, because the mean of its divisors is an integer number (2725024).

Almost surely, 2^20985109 is an apocalyptic number.

It is an amenable number.

20985109 is a deficient number, since it is larger than the sum of its proper divisors (815083).

20985109 is a wasteful number, since it uses less digits than its factorization.

20985109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4347.

The product of its (nonzero) digits is 6480, while the sum is 34.

The square root of 20985109 is about 4580.9506655278. The cubic root of 20985109 is about 275.8271908852.

The spelling of 20985109 in words is "twenty million, nine hundred eighty-five thousand, one hundred nine".