820717 has 4 divisors (see below), whose sum is σ = 829276. Its totient is φ = 812160.

The previous prime is 820711. The next prime is 820723. The reversal of 820717 is 717028.

It is a happy number.

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

It is an interprime number because it is at equal distance from previous prime (820711) and next prime (820723).

It can be written as a sum of positive squares in 2 ways, for example, as 538756 + 281961 = 734^2 + 531^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-820717 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 7.

It is a zygodrome in base 7.

It is a junction number, because it is equal to n+sod(n) for n = 820691 and 820700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4134 + ... + 4327.

It is an arithmetic number, because the mean of its divisors is an integer number (207319).

2⁸²⁰⁷¹⁷ is an apocalyptic number.

It is an amenable number.

820717 is a deficient number, since it is larger than the sum of its proper divisors (8559).

820717 is an equidigital number, since it uses as much as digits as its factorization.

820717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8558.

The product of its (nonzero) digits is 784, while the sum is 25.

The square root of 820717 is about 905.9343243304. The cubic root of 820717 is about 93.6262889728.

The spelling of 820717 in words is "eight hundred twenty thousand, seven hundred seventeen".