20417 has 4 divisors (see below), whose sum is σ = 21636. Its totient is φ = 19200.

The previous prime is 20411. The next prime is 20431. The reversal of 20417 is 71402.

It is a happy number.

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 5776 + 14641 = 76^2 + 121^2 .

It is a cyclic number.

It is not a de Polignac number, because 20417 - 2⁶ = 20353 is a prime.

It is a Duffinian number.

It is a plaindrome in base 7.

It is a nialpdrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (20411) 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, 584 + ... + 617.

It is an arithmetic number, because the mean of its divisors is an integer number (5409).

2²⁰⁴¹⁷ is an apocalyptic number.

It is an amenable number.

20417 is a deficient number, since it is larger than the sum of its proper divisors (1219).

20417 is a wasteful number, since it uses less digits than its factorization.

20417 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1218.

The product of its (nonzero) digits is 56, while the sum is 14.

The square root of 20417 is about 142.8880680813. Note that the first 3 decimals coincide. The cubic root of 20417 is about 27.3315320381.

Adding to 20417 its reverse (71402), we get a palindrome (91819).

It can be divided in two parts, 2041 and 7, that added together give a 11-th power (2048 = 2¹¹).

The spelling of 20417 in words is "twenty thousand, four hundred seventeen", and thus it is an iban number.