20811169 has 4 divisors (see below), whose sum is σ = 20920320. Its totient is φ = 20702020.

The previous prime is 20811157. The next prime is 20811173. The reversal of 20811169 is 96111802.

It is a happy number.

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 a cyclic number.

It is not a de Polignac number, because 20811169 - 2⁷ = 20811041 is a prime.

It is a super-2 number, since 2×20811169² = 866209510293122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20811569) 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 3 ways as a sum of consecutive naturals, for example, 54289 + ... + 54670.

It is an arithmetic number, because the mean of its divisors is an integer number (5230080).

Almost surely, 2^20811169 is an apocalyptic number.

It is an amenable number.

20811169 is a deficient number, since it is larger than the sum of its proper divisors (109151).

20811169 is a wasteful number, since it uses less digits than its factorization.

20811169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109150.

The product of its (nonzero) digits is 864, while the sum is 28.

The square root of 20811169 is about 4561.9260186899. The cubic root of 20811169 is about 275.0629894278.

The spelling of 20811169 in words is "twenty million, eight hundred eleven thousand, one hundred sixty-nine".