820690 has 32 divisors (see below), whose sum is σ = 1632960. Its totient is φ = 295104.

The previous prime is 820681. The next prime is 820691. The reversal of 820690 is 96028.

It is a super-2 number, since 2×820690² = 1347064152200, which contains 22 as substring.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (820691) by changing a digit.

820690 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, 7617 + ... + 7723.

It is an arithmetic number, because the mean of its divisors is an integer number (51030).

2⁸²⁰⁶⁹⁰ is an apocalyptic number.

820690 is a deficient number, since it is larger than the sum of its proper divisors (812270).

820690 is a wasteful number, since it uses less digits than its factorization.

820690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 820690 is about 905.9194224654. The cubic root of 820690 is about 93.6252622537.

The spelling of 820690 in words is "eight hundred twenty thousand, six hundred ninety".