820205 has 8 divisors (see below), whose sum is σ = 1008504. Its totient is φ = 640000.

The previous prime is 820201. The next prime is 820213. The reversal of 820205 is 502028.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 51076 + 769129 = 226^2 + 877^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 820205 - 2² = 820201 is a prime.

It is a Duffinian number.

It is a zygodrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820201) 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 7 ways as a sum of consecutive naturals, for example, 1796 + ... + 2205.

It is an arithmetic number, because the mean of its divisors is an integer number (126063).

2⁸²⁰²⁰⁵ is an apocalyptic number.

It is an amenable number.

820205 is a deficient number, since it is larger than the sum of its proper divisors (188299).

820205 is a wasteful number, since it uses less digits than its factorization.

820205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4047.

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 820205 is about 905.6516990543. The cubic root of 820205 is about 93.6068154995.

It can be divided in two parts, 820 and 205, that multiplied together give a square (168100 = 410²).

The spelling of 820205 in words is "eight hundred twenty thousand, two hundred five".