820217 has 4 divisors (see below), whose sum is σ = 822096. Its totient is φ = 818340.

The previous prime is 820213. The next prime is 820223. The reversal of 820217 is 712028.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 820217 - 2² = 820213 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (820213) 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, 98 + ... + 1284.

It is an arithmetic number, because the mean of its divisors is an integer number (205524).

2⁸²⁰²¹⁷ is an apocalyptic number.

It is an amenable number.

820217 is a deficient number, since it is larger than the sum of its proper divisors (1879).

820217 is a wasteful number, since it uses less digits than its factorization.

820217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1878.

The product of its (nonzero) digits is 224, while the sum is 20.

The square root of 820217 is about 905.6583240936. The cubic root of 820217 is about 93.6072720018.

It can be divided in two parts, 82021 and 7, that added together give a palindrome (82028).

The spelling of 820217 in words is "eight hundred twenty thousand, two hundred seventeen".