20811771 has 6 divisors (see below), whose sum is σ = 30061460. Its totient is φ = 13874508.

The previous prime is 20811767. The next prime is 20811773. The reversal of 20811771 is 17711802.

It is not a de Polignac number, because 20811771 - 2² = 20811767 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20811773) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1156201 + ... + 1156218.

Almost surely, 2^20811771 is an apocalyptic number.

20811771 is a deficient number, since it is larger than the sum of its proper divisors (9249689).

20811771 is a wasteful number, since it uses less digits than its factorization.

20811771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2312425 (or 2312422 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 27.

The square root of 20811771 is about 4561.9919991162. The cubic root of 20811771 is about 275.0656416306.

The spelling of 20811771 in words is "twenty million, eight hundred eleven thousand, seven hundred seventy-one".