820564 has 6 divisors (see below), whose sum is σ = 1435994. Its totient is φ = 410280.

The previous prime is 820559. The next prime is 820577. The reversal of 820564 is 465028.

It can be written as a sum of positive squares in only one way, i.e., 562500 + 258064 = 750^2 + 508^2 .

It is a nialpdrome in base 16.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102567 + ... + 102574.

2⁸²⁰⁵⁶⁴ is an apocalyptic number.

It is an amenable number.

820564 is a deficient number, since it is larger than the sum of its proper divisors (615430).

820564 is a wasteful number, since it uses less digits than its factorization.

820564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205145 (or 205143 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 820564 is about 905.8498771872. The cubic root of 820564 is about 93.6204706000.

The spelling of 820564 in words is "eight hundred twenty thousand, five hundred sixty-four".