20135 has 4 divisors (see below), whose sum is σ = 24168. Its totient is φ = 16104.

The previous prime is 20129. The next prime is 20143. The reversal of 20135 is 53102.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20135 - 2⁶ = 20071 is a prime.

It is a Duffinian number.

20135 is a modest number, since divided by 135 gives 20 as remainder.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2009 + ... + 2018.

It is an arithmetic number, because the mean of its divisors is an integer number (6042).

2²⁰¹³⁵ is an apocalyptic number.

20135 is a deficient number, since it is larger than the sum of its proper divisors (4033).

20135 is an equidigital number, since it uses as much as digits as its factorization.

20135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4032.

The product of its (nonzero) digits is 30, while the sum is 11.

The square root of 20135 is about 141.8978505827. The cubic root of 20135 is about 27.2051136579.

Adding to 20135 its reverse (53102), we get a palindrome (73237).

The spelling of 20135 in words is "twenty thousand, one hundred thirty-five".