20009911 has 4 divisors (see below), whose sum is σ = 20655424. Its totient is φ = 19364400.

The previous prime is 20009887. The next prime is 20009917. The reversal of 20009911 is 11990002.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20009911 - 2¹¹ = 20007863 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20009917) 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, 322710 + ... + 322771.

It is an arithmetic number, because the mean of its divisors is an integer number (5163856).

Almost surely, 2^20009911 is an apocalyptic number.

20009911 is a deficient number, since it is larger than the sum of its proper divisors (645513).

20009911 is an equidigital number, since it uses as much as digits as its factorization.

20009911 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 645512.

The product of its (nonzero) digits is 162, while the sum is 22.

The square root of 20009911 is about 4473.2439012421. The cubic root of 20009911 is about 271.4865919101.

Adding to 20009911 its reverse (11990002), we get a palindrome (31999913).

It can be divided in two parts, 2000 and 9911, that added together give a palindrome (11911).

The spelling of 20009911 in words is "twenty million, nine thousand, nine hundred eleven".