20909109 has 16 divisors (see below), whose sum is σ = 30109184. Its totient is φ = 12830400.

The previous prime is 20909089. The next prime is 20909117. The reversal of 20909109 is 90190902.

It is not a de Polignac number, because 20909109 - 2⁷ = 20908981 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 (20909209) 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 15 ways as a sum of consecutive naturals, for example, 20604 + ... + 21594.

It is an arithmetic number, because the mean of its divisors is an integer number (1881824).

Almost surely, 2^20909109 is an apocalyptic number.

It is an amenable number.

20909109 is a deficient number, since it is larger than the sum of its proper divisors (9200075).

20909109 is a wasteful number, since it uses less digits than its factorization.

20909109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1548.

The product of its (nonzero) digits is 1458, while the sum is 30.

The square root of 20909109 is about 4572.6479199693. The cubic root of 20909109 is about 275.4938080718.

The spelling of 20909109 in words is "twenty million, nine hundred nine thousand, one hundred nine".