20085 has 16 divisors (see below), whose sum is σ = 34944. Its totient is φ = 9792.

The previous prime is 20071. The next prime is 20089. The reversal of 20085 is 58002.

It is not a de Polignac number, because 20085 - 2⁶ = 20021 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (15).

20085 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20089) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 144 + ... + 246.

It is an arithmetic number, because the mean of its divisors is an integer number (2184).

2²⁰⁰⁸⁵ is an apocalyptic number.

It is an amenable number.

20085 is a deficient number, since it is larger than the sum of its proper divisors (14859).

20085 is a wasteful number, since it uses less digits than its factorization.

20085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124.

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 20085 is about 141.7215579931. The cubic root of 20085 is about 27.1825760669.

Adding to 20085 its sum of digits (15), we get a triangular number (20100 = T₂₀₀).

Adding to 20085 its reverse (58002), we get a palindrome (78087).

The spelling of 20085 in words is "twenty thousand, eighty-five".