20811071 has 8 divisors (see below), whose sum is σ = 21202944. Its totient is φ = 20421720.

The previous prime is 20811041. The next prime is 20811079. The reversal of 20811071 is 17011802.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20811071 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 (20811079) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25256 + ... + 26066.

It is an arithmetic number, because the mean of its divisors is an integer number (2650368).

Almost surely, 2^20811071 is an apocalyptic number.

20811071 is a deficient number, since it is larger than the sum of its proper divisors (391873).

20811071 is an equidigital number, since it uses as much as digits as its factorization.

20811071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1261.

The product of its (nonzero) digits is 112, while the sum is 20.

The square root of 20811071 is about 4561.9152776000. The cubic root of 20811071 is about 275.0625576690.

Adding to 20811071 its reverse (17011802), we get a palindrome (37822873).

The spelling of 20811071 in words is "twenty million, eight hundred eleven thousand, seventy-one".