820520 has 32 divisors (see below), whose sum is σ = 1878120. Its totient is φ = 322560.

The previous prime is 820489. The next prime is 820537. The reversal of 820520 is 25028.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 729316 + 91204 = 854^2 + 302^2 .

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 2780 + ... + 3060.

2⁸²⁰⁵²⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 820520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (939060).

820520 is an abundant number, since it is smaller than the sum of its proper divisors (1057600).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

820520 is a wasteful number, since it uses less digits than its factorization.

820520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 365 (or 361 counting only the distinct ones).

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

The square root of 820520 is about 905.8255902766. The cubic root of 820520 is about 93.6187972086.

Adding to 820520 its reverse (25028), we get a palindrome (845548).

The spelling of 820520 in words is "eight hundred twenty thousand, five hundred twenty".