820290 has 32 divisors (see below), whose sum is σ = 2024640. Its totient is φ = 212544.

The previous prime is 820279. The next prime is 820319. The reversal of 820290 is 92028.

It is a nialpdrome in base 16.

It is an unprimeable number.

820290 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 741 + ... + 1479.

It is an arithmetic number, because the mean of its divisors is an integer number (63270).

2⁸²⁰²⁹⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 820290, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1012320).

820290 is an abundant number, since it is smaller than the sum of its proper divisors (1204350).

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

820290 is a wasteful number, since it uses less digits than its factorization.

820290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 786.

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 820290 is about 905.6986253716. The cubic root of 820290 is about 93.6100489613.

The spelling of 820290 in words is "eight hundred twenty thousand, two hundred ninety".