820709 has 8 divisors (see below), whose sum is σ = 907200. Its totient is φ = 738496.

The previous prime is 820691. The next prime is 820711. The reversal of 820709 is 907028.

820709 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 820709 - 2¹⁶ = 755173 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 7.

It is a zygodrome in base 7.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820759) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 659 + ... + 1440.

It is an arithmetic number, because the mean of its divisors is an integer number (113400).

2⁸²⁰⁷⁰⁹ is an apocalyptic number.

It is an amenable number.

820709 is a deficient number, since it is larger than the sum of its proper divisors (86491).

820709 is a wasteful number, since it uses less digits than its factorization.

820709 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2139.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 820709 is about 905.9299089885. The cubic root of 820709 is about 93.6259847621.

The spelling of 820709 in words is "eight hundred twenty thousand, seven hundred nine".