20017 has 4 divisors (see below), whose sum is σ = 20596. Its totient is φ = 19440.

The previous prime is 20011. The next prime is 20021. The reversal of 20017 is 71002.

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

It can be written as a sum of positive squares in 2 ways, for example, as 13456 + 6561 = 116^2 + 81^2 .

It is a cyclic number.

It is not a de Polignac number, because 20017 - 2⁷ = 19889 is a prime.

It is a Duffinian number.

20017 is a lucky number.

It is a plaindrome in base 7.

It is a junction number, because it is equal to n+sod(n) for n = 19985 and 20012.

It is not an unprimeable number, because it can be changed into a prime (20011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 234 + ... + 307.

It is an arithmetic number, because the mean of its divisors is an integer number (5149).

2²⁰⁰¹⁷ is an apocalyptic number.

It is an amenable number.

20017 is a deficient number, since it is larger than the sum of its proper divisors (579).

20017 is an equidigital number, since it uses as much as digits as its factorization.

20017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 578.

The product of its (nonzero) digits is 14, while the sum is 10.

The square root of 20017 is about 141.4814475470. The cubic root of 20017 is about 27.1518648378.

Adding to 20017 its reverse (71002), we get a palindrome (91019).

The spelling of 20017 in words is "twenty thousand, seventeen", and thus it is an iban number.