20684 has 6 divisors (see below), whose sum is σ = 36204. Its totient is φ = 10340.

The previous prime is 20681. The next prime is 20693. The reversal of 20684 is 48602.

It is a nialpdrome in base 13 and base 14.

It is not an unprimeable number, because it can be changed into a prime (20681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2582 + ... + 2589.

It is an arithmetic number, because the mean of its divisors is an integer number (6034).

2²⁰⁶⁸⁴ is an apocalyptic number.

It is an amenable number.

20684 is a deficient number, since it is larger than the sum of its proper divisors (15520).

20684 is a wasteful number, since it uses less digits than its factorization.

20684 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5175 (or 5173 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 20684 is about 143.8193311068. The cubic root of 20684 is about 27.4501576517.

The spelling of 20684 in words is "twenty thousand, six hundred eighty-four".