20171 has 4 divisors (see below), whose sum is σ = 21072. Its totient is φ = 19272.

The previous prime is 20161. The next prime is 20173. The reversal of 20171 is 17102.

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 20171 - 2⁶ = 20107 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20173) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 416 + ... + 461.

It is an arithmetic number, because the mean of its divisors is an integer number (5268).

2²⁰¹⁷¹ is an apocalyptic number.

20171 is a deficient number, since it is larger than the sum of its proper divisors (901).

20171 is an equidigital number, since it uses as much as digits as its factorization.

20171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 900.

The product of its (nonzero) digits is 14, while the sum is 11.

The square root of 20171 is about 142.0246457485. The cubic root of 20171 is about 27.2213176308.

Adding to 20171 its reverse (17102), we get a palindrome (37273).

It can be divided in two parts, 201 and 71, that added together give a palindrome (272).

The spelling of 20171 in words is "twenty thousand, one hundred seventy-one", and thus it is an iban number.