820045 has 8 divisors (see below), whose sum is σ = 988920. Its totient is φ = 652800.

The previous prime is 820037. The next prime is 820051. The reversal of 820045 is 540028.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 509796 + 310249 = 714^2 + 557^2 .

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

It is not a de Polignac number, because 820045 - 2³ = 820037 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1801 + ... + 2209.

It is an arithmetic number, because the mean of its divisors is an integer number (123615).

2⁸²⁰⁰⁴⁵ is an apocalyptic number.

It is an amenable number.

820045 is a deficient number, since it is larger than the sum of its proper divisors (168875).

820045 is a wasteful number, since it uses less digits than its factorization.

820045 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 815.

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 820045 is about 905.5633605662. The cubic root of 820045 is about 93.6007283772.

The spelling of 820045 in words is "eight hundred twenty thousand, forty-five".