20684871 has 12 divisors (see below), whose sum is σ = 30115072. Its totient is φ = 13680576.

The previous prime is 20684837. The next prime is 20684879. The reversal of 20684871 is 17848602.

It is not a de Polignac number, because 20684871 - 2¹⁵ = 20652103 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 (20684879) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7906 + ... + 10191.

Almost surely, 2^20684871 is an apocalyptic number.

20684871 is a deficient number, since it is larger than the sum of its proper divisors (9430201).

20684871 is a wasteful number, since it uses less digits than its factorization.

20684871 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18230 (or 18227 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 20684871 is about 4548.0623346652. The cubic root of 20684871 is about 274.5054295362.

The spelling of 20684871 in words is "twenty million, six hundred eighty-four thousand, eight hundred seventy-one".