20289909 has 4 divisors (see below), whose sum is σ = 27053216. Its totient is φ = 13526604.

The previous prime is 20289889. The next prime is 20289911. The reversal of 20289909 is 90998202.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20289909 - 2⁵ = 20289877 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 (20289989) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3381649 + ... + 3381654.

It is an arithmetic number, because the mean of its divisors is an integer number (6763304).

Almost surely, 2^20289909 is an apocalyptic number.

It is an amenable number.

20289909 is a deficient number, since it is larger than the sum of its proper divisors (6763307).

20289909 is an equidigital number, since it uses as much as digits as its factorization.

20289909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6763306.

The product of its (nonzero) digits is 23328, while the sum is 39.

The square root of 20289909 is about 4504.4321506712. The cubic root of 20289909 is about 272.7470318310.

The spelling of 20289909 in words is "twenty million, two hundred eighty-nine thousand, nine hundred nine".