20800811 has 4 divisors (see below), whose sum is σ = 20809992. Its totient is φ = 20791632.

The previous prime is 20800807. The next prime is 20800841. The reversal of 20800811 is 11800802.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20800811 - 2² = 20800807 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20800841) 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, 1520 + ... + 6626.

It is an arithmetic number, because the mean of its divisors is an integer number (5202498).

Almost surely, 2^20800811 is an apocalyptic number.

20800811 is a deficient number, since it is larger than the sum of its proper divisors (9181).

20800811 is an equidigital number, since it uses as much as digits as its factorization.

20800811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9180.

The product of its (nonzero) digits is 128, while the sum is 20.

The square root of 20800811 is about 4560.7906112866. The cubic root of 20800811 is about 275.0173476660.

Subtracting from 20800811 its reverse (11800802), we obtain a palindrome (9000009).

The spelling of 20800811 in words is "twenty million, eight hundred thousand, eight hundred eleven".