20901909 has 8 divisors (see below), whose sum is σ = 31850560. Its totient is φ = 11943936.

The previous prime is 20901901. The next prime is 20901911. The reversal of 20901909 is 90910902.

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

It is not a de Polignac number, because 20901909 - 2³ = 20901901 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20901901) 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 7 ways as a sum of consecutive naturals, for example, 497644 + ... + 497685.

It is an arithmetic number, because the mean of its divisors is an integer number (3981320).

Almost surely, 2^20901909 is an apocalyptic number.

It is an amenable number.

20901909 is a deficient number, since it is larger than the sum of its proper divisors (10948651).

20901909 is an equidigital number, since it uses as much as digits as its factorization.

20901909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 995339.

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

The square root of 20901909 is about 4571.8605621782. The cubic root of 20901909 is about 275.4621825709.

The spelling of 20901909 in words is "twenty million, nine hundred one thousand, nine hundred nine".