820730 has 8 divisors (see below), whose sum is σ = 1477332. Its totient is φ = 328288.

The previous prime is 820723. The next prime is 820733. The reversal of 820730 is 37028.

820730 = 256² + 257² + ... + 267².

It can be written as a sum of positive squares in 2 ways, for example, as 674041 + 146689 = 821^2 + 383^2 .

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

It is a nialpdrome in base 7.

It is not an unprimeable number, because it can be changed into a prime (820733) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41027 + ... + 41046.

2⁸²⁰⁷³⁰ is an apocalyptic number.

820730 is a deficient number, since it is larger than the sum of its proper divisors (656602).

820730 is a wasteful number, since it uses less digits than its factorization.

820730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82080.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 820730 is about 905.9414992150. The cubic root of 820730 is about 93.6267833110.

Adding to 820730 its reverse (37028), we get a palindrome (857758).

The spelling of 820730 in words is "eight hundred twenty thousand, seven hundred thirty".