20684161 has 16 divisors (see below), whose sum is σ = 22302720. Its totient is φ = 19146960.

The previous prime is 20684159. The next prime is 20684171. The reversal of 20684161 is 16148602.

It is a cyclic number.

It is not a de Polignac number, because 20684161 - 2¹ = 20684159 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20684171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 78516 + ... + 78778.

It is an arithmetic number, because the mean of its divisors is an integer number (1393920).

Almost surely, 2^20684161 is an apocalyptic number.

It is an amenable number.

20684161 is a deficient number, since it is larger than the sum of its proper divisors (1618559).

20684161 is a wasteful number, since it uses less digits than its factorization.

20684161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 396.

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 20684161 is about 4547.9842787767. The cubic root of 20684161 is about 274.5022887369.

The spelling of 20684161 in words is "twenty million, six hundred eighty-four thousand, one hundred sixty-one".