820729 has 16 divisors (see below), whose sum is σ = 1048320. Its totient is φ = 624960.

The previous prime is 820723. The next prime is 820733. The reversal of 820729 is 927028.

It is not a de Polignac number, because 820729 - 2¹⁹ = 296441 is a prime.

It is an Ulam number.

It is a nialpdrome in base 7.

It is a junction number, because it is equal to n+sod(n) for n = 820697 and 820706.

It is not an unprimeable number, because it can be changed into a prime (820723) 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 15 ways as a sum of consecutive naturals, for example, 2484 + ... + 2794.

It is an arithmetic number, because the mean of its divisors is an integer number (65520).

2⁸²⁰⁷²⁹ is an apocalyptic number.

It is an amenable number.

820729 is a deficient number, since it is larger than the sum of its proper divisors (227591).

820729 is a wasteful number, since it uses less digits than its factorization.

820729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 360.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 820729 is about 905.9409473029. The cubic root of 820729 is about 93.6267452852.

The spelling of 820729 in words is "eight hundred twenty thousand, seven hundred twenty-nine".